NEW YORK, Oct 26 — When Candace Nelson opened the first Sprinkles bakery in Los Angeles in 2005, she did not actually have any sprinkles on hand. "I liked the word, but I thought of them as a supermarket pick, waxy and fake,” she said. "Not elegant, chic and modern.”

Rainbow sprinkles (also called jimmies in parts of the Northeast) are made from sugar, various waxy shortenings and bright artificial colours. They did not align with Nelson’s vision for "elevated” cupcakes, which are made from quality ingredients like Madagascar vanilla and Dutch cocoa, and topped with a two-tone button of colour that she calls a "modern dot”.

"The top is the aspirational part of the cupcake,” she said. "I wanted it to have a more evolved aesthetic.”

But Nelson did not reckon with the awesome power of rainbow sprinkles.

In the intervening years, largely through photo-friendly social media sites like Pinterest and Instagram, they have coated the entire world of baking — and beyond. Rainbow sprinkles (also known as Funfetti and unicorn food) first invaded cookies and waffles; then marched on, swarming over cocktails and croissants, and finally, as a design motif, onto phone cases, scented candles and press-on nails.

The movement began in 1989, when Pillsbury introduced a Funfetti cake mix, a white cake mix with multicoloured sprinkles included in the box. The revolutionary twist: The sprinkles were for colouring the batter, not for decorating the top. In a hot oven, the sprinkles melted into streaks and dots of bright colour that instantly made plain cake obsolete for a certain demographic: Kids.

"In the 1990s, to have a successful birthday party, you had to beg your mom for Funfetti cake,” said Molly Yeh, a baker and food blogger best known for her from-scratch version of the cake. "It was as if chocolate and vanilla no longer existed.”

Funfetti copycats multiplied. In 1990, Betty Crocker brought out Dunkaroos, a snack pack of cookies with sprinkle-spiked frosting for dipping. (They are no longer sold in the United States, but there is a thriving trade on eBay for the Canadian product.)

Dannon Sprinkl’ins, yogurt with rainbow sprinkles packed on top, arrived in 1992. Pillsbury owns the trademark for the word, but it became so popular as people grew up with it that it is now a synonym for rainbow sprinkles, the way Kleenex is for tissues.

The members of this Funfetti generation (some call them millennials) are now adults. Some are pastry chefs, like Christina Tosi of Milk Bar in New York, the first baker to reinject rainbow sprinkles into the realm of cool.

Her Birthday Cake, packed with sprinkles, was one of the nostalgic creations — along with Cereal Milk soft-serve and Candy Bar pie — that instantly put her on the map in 2008.

The Milk Bar Birthday Cake, in New York, October 19, 2016. — Picture by Danny Ghitis/The New York Times

But her baking experiments began long ago — with Funfetti. "I loved transforming cake mixes into cake-mix cookies,” said Tosi, 34. "They were sandy but fudgy. The Funfetti cookie was my favourite one to bring around the neighbourhood.” Birthday Cake remains the bakery’s best-selling cake, and in homage, an entire wall of the newest Milk Bar outpost, in the Manhattan neighbourhood of NoLIta, is coated with (plastic) rainbow sprinkles.

In home kitchens, rainbow sprinkles showed up in pancakes and waffles, cookies and cupcakes. "They’re just so photogenic,” said Yeh, who put them in unlikely places like tahini blondie ice cream sandwiches and mandelbrot. "I think of it like garnishing a dish with parsley, and they make anything look festive.” (True story: At Yeh’s 2014 wedding, guests threw rainbow sprinkles instead of rice.)

On Instagram and Pinterest, Funfetti has run rampant, transforming formerly plain food like cheesecake, sugar cookies and even oatmeal into dizzying rainbow treats. You can marvel at Funfetti martinis (made with white chocolate liqueur and cake-flavoured vodka and rimmed with sprinkles), Funfetti cheese balls (sweetened cream cheese coated with sprinkles) and rainbow sprinkle cinnamon rolls. According to Pinterest, in the last year, users 25- to 34-years-old have saved 260 per cent more Funfetti ideas than the year before. Among all users, the increase is 20 per cent.

"We are obsessed with Funfetti, and we’re the first generation to grow up with social media,” said Yeh, 27. "The combination of that and nostalgia explains why rainbow sprinkles are all over the internet.”

In the real world, rainbow sprinkles have been vaulting up the food chain. At Faun, an ambitious New York restaurant, a slice of Gorgonzola crusted with rainbow sprinkles is sometimes served as the cheese course.

At high-end bakeries, rainbow sprinkles are being baked into puff pastry for croissants, dotted onto French-style macarons and deployed to cover giant Funfetti wedding cakes.

At Black Tap, a Manhattan mini-chain known for inflated milk shakes, one specialty is a tall vanilla shake topped with a hefty slice of vanilla cake resting on the rim of the glass. Whipped cream is piled above, and the entire creation (including the glass) is plastered with rainbow sprinkles.

In Brooklyn, there is a hip, slightly ironic diner where the husband-and-wife owners produce rainbow sprinkles from scratch.

"There is no end to making sprinkles,” said Sohla el-Waylly, who devised the method used at Hail Mary diner in Greenpoint. It requires egg whites, confectioners’ sugar, food colouring, patience and a pastry bag. The mixture can also be flavoured; el-Waylly likes rose and vanilla. The mixture is piped in skinny lines onto parchment paper, allowed to air-dry, and then chopped or broken — or not.

The diner’s tall vanilla layer cake is plastered with "sprinkles” that are as long and thin as a pretzel stick, giving it an eccentric, shaggy quality that clearly does not come from a box.

Fortunately there is no need to make your own sprinkles, especially to put in cake, where the commercial kind is preferred. The choice seems endless: At craft and baking shops, the selection has proliferated, with rainbow confetti, stars, flowers and hearts. Amy Sedaris, the actor, writer and doyenne of eccentric entertaining, recently released her own rainbow mix of sprinkles and "decorettes”, for topping cupcakes, popcorn and French fries.

Nonpareils, tiny round candies that are a European relative of our sprinkles, are also popular in rainbow colours. But rainbow sprinkles — the cylindrical, waxy kind invented in the United States around 1920 — have a special place in the hearts of many Americans.

When the Big Gay Ice Cream soft-serve truck got rolling in 2009, naturally rainbow sprinkles were one of its signatures. "We put big honking layers of sprinkles wherever we can,” said Doug Quint, a founder.

The Merlin cone wears a thick Elizabethan ruff of rainbow sprinkles, and even an order for a plain vanilla cup arrives as a parfait, striped with sprinkles. "With soft-serve, there aren’t many toppings or mix-ins that we can use, so sprinkles are particularly important,” he said.

Quint, who constantly tests new brands and mixtures, says that sprinkles are not merely decoration; he loves their "waxy crunch” and trace of vanilla flavour. "They are candy, after all,” he said.

He also has strong feelings about colours. "White is a waste of real estate,” he said, advising me to buy solid-coloured sprinkles and concoct my own rainbow mixture. "Use half as much yellow as everything else,” were his parting words.

I made Quint my sprinkles mentor as I set out to bake a homemade Funfetti cake, using a recipe from The Sprinkles Baking Book, Nelson’s new cookbook.

Apparently, by 2015, her aesthetic had evolved (or devolved) to include rainbow sprinkles. The 10-year birthday cake she devised for her empire, which now includes 20 stores and 12 Cupcake ATMs, is the "Sprinkles Sprinkle Cake,” with handfuls of sprinkles both outside the cake and in.

With white frosting and my new house blend (two parts blue, one part pink, one part orange and one part yellow sprinkles), the effect was brightly irresistible.

It tastes like a vanilla cake, but it looks like a happy childhood.

Rainbow Sprinkle Cake

Yield: 8 to 10 servings

Total time: 1 1/2 hours, plus cooling

For the cake:

1/2 cup/110g unsalted butter (1 stick), slightly softened, more for pans

1 1/2 cups/190g all-purpose flour, more for pans

1 teaspoon baking powder

1/4 teaspoon baking soda

1/4 teaspoon fine salt

2/3 cup/158ml whole milk

1 1/2 teaspoons pure vanilla extract

1 cup/200g sugar

1 whole egg plus 2 egg whites

1/3 cup rainbow sprinkles (not pastel, or naturally coloured)

For the frosting:

8 ounces/225g cream cheese, slightly softened

1/2 cup/110g unsalted butter (1 stick), slightly softened

1/8 teaspoon fine salt, more to taste

3 cups/300g confectioners’ sugar, sifted, more to taste

1/2 teaspoon pure vanilla extract

1 cup rainbow sprinkles

1. Make the cake: Heat oven to 325 degrees and place a rack in the centre. Butter and line the bottoms of two 8-inch round cake pans with parchment paper. Butter the parchment. Flour the pans, coating the bottom and sides, then tap out any excess flour.

2. In a medium bowl, whisk together flour, baking powder, baking soda and salt. In a small bowl, stir together milk and vanilla.

3. In a mixer fitted with the paddle attachment, beat butter and sugar at medium-high speed until light and fluffy, 2 to 3 minutes. Reduce speed to low and, with mixer running, slowly add egg and whites and beat until smooth and creamy, 1 to 2 minutes. Scrape down bowl. Add half the flour mixture, then the milk mixture, then the remaining flour mixture, beating to blend after each addition. Scrape down bowl and blend once more. Remove bowl and use a spatula or spoon to mix in sprinkles by hand.

4. Divide batter evenly between the pans and bake until the tops are just dry to the touch and a toothpick inserted into the centre comes out clean, 20 to 25 minutes. Rotate the pans halfway through baking.

5. Transfer pans to a wire rack and let cool completely, at least 4 hours, before turning out.

6. Make the frosting: In a mixer fitted with the paddle attachment, beat cream cheese, butter and salt together at medium speed until light and fluffy, 2 minutes. Reduce speed to low and, with mixer running, slowly add sugar and beat until smooth. Beat in vanilla just until incorporated. Taste frosting; you should be able to taste the cream cheese and a little bit of saltiness, as well as the sweetness. If desired, add more salt or sugar. Keep refrigerated.

7. Turn cooled cakes out of pans. Using a bread knife, cut off any domed or uneven parts of each cake to make flat surfaces. Place one of the cakes on a platter or a cake stand, cut side up. Using an offset spatula, frost the top. Stack the other layer on top, cut side down. Place remaining frosting on top of the cake and, working from the centre outward, frost the top and sides of the cake.

8. Place a baking sheet under the platter or cake stand, to catch any fallen sprinkles. Sprinkle the top with a layer of sprinkles. Toss remaining sprinkles at the sides of the cake, or press handfuls of sprinkles gently up the sides to make a thicker coating. Gather fallen sprinkles and repeat until coated to your liking.

9. Refrigerate cake 30 minutes or longer to set. Serve cool. — The New York Times