Ingredients:

  • 1 1/2 cups All-Purpose Flour (sifted)
  • 1 cup Granulated Sugar (for cake)
  • 1/2 cup Unsweetened High-Quality Cocoa Powder (Dutch-processed recommended)
  • 1 teaspoon Baking Soda
  • 1/2 teaspoon Baking Powder
  • 1/2 teaspoon Fine Sea Salt (for cake)
  • 2 Large Eggs
  • 1/2 cup Whole Milk
  • 1/4 cup Vegetable Oil
  • 1 teaspoon Vanilla Extract (for cake)
  • 1/2 cup Hot Water or Hot Black Coffee
  • 1 cup Granulated Sugar (for caramel)
  • 1/4 cup Water (for caramel)
  • 1/2 cup Heavy Cream (warmed slightly)
  • 2 tablespoons Unsalted Butter (for caramel, cut into cubes)
  • 1/2 teaspoon Flaky Sea Salt (for caramel)
  • 1 cup Unsalted Butter (for frosting, softened)
  • 3 cups Powdered Sugar (sifted)
  • 1/2 cup Cooled Salted Caramel Sauce (MUST BE COMPLETELY COOL)
  • 1/2 teaspoon Vanilla Extract (for frosting)
  • 1/4 teaspoon Pinch of Salt (for frosting, if needed)

Instructions:

  1. Phase 1: Start the Caramel. Combine 1 cup granulated sugar and 1/4 cup water in a medium heavy-bottomed saucepan. Heat gently until the sugar dissolves.
  2. Cook the Caramel: Increase heat to medium-high. Do not stir—swirl the pan occasionally—until the mixture turns a deep amber color.
  3. Stop the Cook: Remove the pan from the heat. Carefully whisk in the warmed heavy cream (it will bubble vigorously!). Whisk until smooth.
  4. Finish and Chill: Stir in the cubed butter and the flaky sea salt. Transfer the sauce to a heatproof bowl and set aside to cool completely (at least 60 minutes) before using.
  5. Phase 2: Preheat oven to 350°F (180°C) and line a 12-cup muffin tin with liners. Combine Dry Ingredients: Whisk together flour, 1 cup sugar, cocoa powder, baking soda, baking powder, and 1/2 teaspoon salt in a large bowl.
  6. Combine Wet Ingredients: In a separate medium bowl, whisk together the eggs, milk, oil, and 1 teaspoon vanilla extract until combined.
  7. Mix Batter: Pour the wet mixture into the dry ingredients. Mix on low speed until just combined. Slowly pour in the hot water or coffee and mix on low speed until the batter is smooth and thin (this is intentional!). Do not overmix.
  8. Bake: Fill cupcake liners about two-thirds full. Bake for 18–20 minutes, or until a skewer comes out clean. Allow the cupcakes to cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely.
  9. Phase 3: Cream the Butter: In an electric mixer, beat the 1 cup of softened butter on medium speed until light and fluffy (3-4 minutes).
  10. Add Sugar: Gradually add the sifted powdered sugar, mixing on low speed until incorporated, then increase speed and beat until smooth.
  11. Whip in Caramel: Pour the completely cooled 1/2 cup of caramel sauce and 1/2 teaspoon vanilla extract into the buttercream. Beat on high speed until the frosting is smooth, light, and perfectly pipeable. Taste and add a pinch of salt if needed.
  12. Assemble: Pipe generous swirls of buttercream onto the cooled cupcakes. Garnish by lightly drizzling any leftover caramel sauce and sprinkling with a tiny pinch of flaky sea salt.