Olive Oil Cake with Dulce de Leche Filling and Chocolate Frosting

It’s a party as long as there’s cake.

Birthday Cake 2021 is an Olive Oil Layer Cake with Dulce de Leche Filling and Chocolate Frosting. A mouthful, indeed, and a twist on a classic.

I turned 40 this month, and in a pandemic-free world, I would’ve had a big party celebrating my and Matt’s birthdays (only two days apart!) and invited our friends and families. But in-person celebrations will have to wait. Instead, I spent my birthday at home, with video calls, our favorite food delivered, and so much sweets. All day long I was showered with love and surprise desserts: a basque cheesecake from Matt, a Milk Bar cake from my team, some French pastries dropped off by one of my closest friends, quarts of small-batch ice cream from another friend, and this homemade birthday cake.

I love making layer cakes for birthdays. The classic birthday cake is typically a vanilla cake with chocolate frosting. My cakes usually have some sort of chocolate or dulce de leche (or both). Matt loves vanilla cake and olive oil cake, really any kind of bouncy cake, and I knew I can combine all of those in a celebration cake.

I made this olive oil snack cake, but used lemon instead of orange, and made it in two round pans instead of a long rectangular one. I used canned dulce de leche because why not? And I whipped up a super-simple milk chocolate sour cream frosting (only 4 ingredients) that lent a creamy tanginess to the bouncy cake and decadent filling.

I may not have had the grand party I had imagined, but this birthday cake was perfect for our little celebration at home. And if you’d like to see birthday cakes from previous years, they’re all here: 2020, 2019, 2018, 2016, 2015, 2014, 2012.

Yield: serves 8-10

Olive Oil Cake with Dulce de Leche Filling and Chocolate Frosting

Prep Time: 20 minutes

Cook Time: 40 minutes

Total Time: 1 hour



1 cup extra virgin olive oil, plus more for pans
2 cups all purpose flour, plus more for pans
1/2 teaspoon salt
1 teaspoon baking powder
1/4 teaspoon baking soda
1 1/2 cups granulated sugar
3 large eggs
3 tablespoons fresh lemon juice, plus freshly-grated zest from one lemon
1 1/4 cups whole 
1 teaspoon vanilla


12 oz milk chocolate
1 cup sour cream
1 teaspoon vanilla
1/4 teaspoon salt


12 oz prepared dulce de leche (I used Nestle La Lechera)


  1. Make the cake. Preheat oven to 375 F.
  2. Grease two 9-inch cake pans with olive oil, and line with parchment paper. Brush with olive oil again and flour, shaking out excess flour. Set aside
  3. In a large bowl, whisk together the dry ingredients: flour, salt, baking powder, and baking soda. Set aside.
  4. Combine 1 1/2 cups sugar, the eggs, and orange zest in a large bowl for an electric mixer. Using the whisk attachment, set mixer on high, and whisk until thick, about 6 minutes. 
  5. Slowly drizzle in olive oil and continue whisking on high until well incorporated, about 2 minutes.
  6. Set mixer speed to low. Add milk, lemon juice, and vanilla. Continue mixing for another minute.
  7. Slowly add the flour mixture and mix until just combined.
  8. Pour batter in greased cake pan. 
  9. Bake for 40 minutes, or until a skewer inserted into the center comes out clean. Cool in pan then transfer to rack to cool completely. (I had made the cakes a day in advance and froze them overnight, then took them out about an hour before I was about to make the frosting.)
  10. Make the frosting. In a microwave-safe bowl, melt the chocolate. Heat on full power for 30 seconds, then remove from microwave and stir. Everything would have started to melt but you’ll still have some lumps. Heat again in 30-second intervals and stir until the mixture turns smooth. I heated everything for a total of 1 1/2 minutes. You can also melt the chocolate in a double broiler.
  11. Pour melted chocolate in a bowl of a standing mixer, or a big bowl you can use with a hand mixer. Add sour cream, vanilla, and salt. Using the whisk attachment, beat at medium speed, scraping bowl as needed, for a total of 1-2 minutes or until smooth and creamy.
  12. Assemble the cake. Slice off any domed tops to have a flat/even surface on both sides of each cake layer. 
  13. Spread the dulce de leche evenly over one layer, then stack the other layer on top.
  14. Frost the top and sides of cake with the chocolate sour cream frosting. Decorate with flowers or sprinkles. Enjoy!