Step 1: Prepare the cupcakes

1. Preheat your oven to 350°F (175°C). Line a 12-cup cupcake pan with paper liners.

2. In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.

3. In a large bowl, use an electric mixer to beat together room temperature butter and light brown sugar for about 2 minutes, until light and creamy.

4. Beat in eggs, one at a time, mixing well after each.

5. Add vanilla extract, sour cream, and vegetable oil. Mix until fully combined. Scrape the sides and bottom of the bowl as needed.

6. Gradually add the dry ingredients in three parts, alternating with the milk, beginning and ending with the dry mix. Stir just until the batter is smooth—do not overmix.

Step 2: Bake the cupcakes

7. Divide the batter evenly between the cupcake liners, filling each about ¾ full.

8. Bake in the preheated oven for 15–18 minutes, or until a toothpick inserted into the center comes out clean.

9. Let cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before filling and frosting.

Step 3: Make the frosting

10. In the bowl of a stand mixer fitted with the paddle or whisk attachment, beat unsalted butter for about 2 minutes until creamy.

11. Gradually add in the confectioners’ sugar and beat on low speed until fully incorporated.

12. Add the dulce de leche and a pinch of salt, then beat until smooth and fluffy.

    • Too thick? Add 1–2 teaspoons of milk.

    • Too thin? Add more sifted sugar.

13. Transfer frosting to a piping bag fitted with your preferred tip.

Step 4: Assemble the cupcakes

14. Once cupcakes are completely cool, core out the center of each using a cupcake corer, paring knife, or the wide end of a piping tip.

15. Fill each hole with 1 to 2 teaspoons of dulce de leche, smoothing the tops.

16. Pipe or spread the prepared frosting over each cupcake.

17. Optional: Drizzle with extra dulce de leche or sprinkle with sea salt for a finishing touch.