Karen Oura’s chantilly cake is so popular with her family that during one month she was asked to make it four times for birthday celebrations. The Wailuku resident has been baking her special dessert for nearly 20 years.

“The cake is easy. The frosting is humbug, but very good,” she said. “Homemade always tastes better than bought.”

Outside Hawaii, if you ask for chantilly, you will get a sweet whipped cream frosting, often made with strawberries.

But here, chantilly cake refers to a chocolate cake covered in a golden, buttery rich chantilly frosting that’s similar to the topping of German chocolate cake, but without coconut. You may be more familiar with it as what people say is the best part of the Coco Puffs sold at Liliha Bakery — the frosting on top.

Oura starts with a boxed cake mix combined with chocolate pudding mix, eggs, water and vegetable oil. She prefers the Betty Crocker brand.

But it is her frosting that steals the show.

Her recipe calls for evaporated milk, salted butter, sugar, egg yolks and vanilla. It isn’t tricky to make, but takes time: The frosting must be stirred constantly for 15 to 20 minutes.

Oura passes the time at the stove by playing games on her phone. As it cooks, the mixture gradually thickens and turns into a magical rich frosting. It thickens further once cooled or refrigerated.

The grandmother of five makes a 9-by-13-inch sheet cake, which provides more pieces than a two-layer round cake.

“Each person eats more than one piece, and you would think there would be leftovers, but there aren’t,” she said.

Oura’s family includes husband Gary, sons Grant and Garren, and daughter Karey Kapoi. “With their spouses and children, the cake doesn’t last.”

Grant operates the popular food truck Ogo in Kahului on Maui. “We are a foodie family,” Oura explained.

She usually bakes her cakes in the morning, as they need to cool before being frosted. She said a finished and frosted cake can be kept in the refrigerator for up to three days, but she recommends letting it come to room temperature, leaving it out at least 1 hour before serving, so the frosting will be creamy.

Her family enjoys the frosting plain, but others like to mix in or garnish with chopped macadamia nuts or shredded coconut.

“I find satisfaction when I bake,” Oura said. And everyone else is satisfied too.

Chocolate Pudding Cake With Chantilly Frosting

• 1 (15.25-ounce) box chocolate cake mix, Betty Crocker brand preferred (disregard directions on box)
• 1 (3.9-ounce) box chocolate instant pudding mix
• 4 large or extra-large eggs
• 1-1/4 cups water
• 1/2 cup vegetable oil, plus more to grease pan
• >> Chantilly frosting:
• 1 (13-ounce) can evaporated milk
• 1-1/2 cups sugar
• 4 large or extra-large egg yolks
• 3/4 cup salted butter
• 1-1/2 teaspoons vanilla extract
• 1-1/3 cups chopped macadamia nuts or coconut (optional)

Heat oven to 350 degrees. Grease a 9-by-13-inch pan or two 8-inch pans or line with parchment.

Combine cake and pudding mixes, eggs and water; pour into pan. Bake 30 to 35 minutes for a 9-by-13-inch pan, or until a pick inserted in center comes out clean (if using 8-inch pans, start checking for doneness at 25 minutes).

Cool at least 4 hours before frosting.

Make frosting: In the top of a double boiler or using a heavy pot such as a Dutch oven, combine milk, sugar, egg yolks, butter and vanilla. Cook over medium heat until thick, about 15 to 20 minutes, stirring constantly with a whisk to keep eggs from scrambling and the frosting from clumping.

Remove from heat. Frosting will thicken as it cools. If desired, mix in coconut or nuts (or save to sprinkle on top of cake as garnish). Frost top of cake (and between layers if making 2 layers). Refrigerate up to three days. Remove cake from refrigerator at least 1 hour before serving. Frosting may also be refrigerated to frost cake later.

Makes 6 to 24 pieces from a 9-by-13-inch cake; 12 slices from a double-layer cake.

Nutritional information unavailable.

Lynette Lo Tom, author of “Back in the Day,” is fascinated by old-fashioned foods. Contact her at 275-3004 or via instagram at brightlightcookery.