- Preheat your oven to 350°F (175°C).
- Grease and line an 8-inch square baking pan or 9-inch round pan with parchment paper, leaving an overhang for easy removal.
Step 2: Make the Brownie Layer
- Melt Butter and Chocolate:
- In a medium saucepan over low heat, melt the butter and chopped chocolate, stirring until smooth. Remove from heat and let cool slightly.
- Mix Wet Ingredients:
- Whisk in the granulated sugar, brown sugar, eggs, and vanilla extract until combined.
- Add Dry Ingredients:
- Sift in the flour, cocoa powder, and salt. Stir until just combined.
- Bake the Brownie Base:
- Pour the brownie batter into the prepared pan and smooth the top.
- Bake for 10–12 minutes. The brownie should be set but not fully cooked. Let it cool slightly while you prepare the butter cake layer.
Step 3: Make the Butter Cake Layer
- Cream Butter and Sugar:
- In a large bowl, use a mixer to beat the butter and sugar until light and fluffy (about 3 minutes).
- Add Eggs and Vanilla:
- Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract.
- Incorporate Dry and Wet Ingredients:
- In a separate bowl, sift together the flour, baking powder, and salt.
- Alternate adding the dry ingredients and milk to the butter mixture, starting and ending with the dry ingredients. Mix until just combined.
Step 4: Assemble and Bake
- Carefully spoon the butter cake batter over the slightly cooled brownie layer. Spread evenly with a spatula.
- Bake for 30–35 minutes, or until the butter cake is golden brown and a toothpick inserted into the center comes out clean.
- Let the cake cool completely in the pan before lifting it out using the parchment paper overhang.
Step 5: Serve
- Slice the cake into squares or wedges for serving.
- Optionally, dust with powdered sugar, drizzle with chocolate ganache, or serve with a scoop of vanilla ice cream for added indulgence.
Storage
- Store leftovers in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 5 days. Bring to room temperature before serving, or reheat slightly for a warm treat.
Tips for the Perfect Brownie Butter Cake
- Don’t Overbake the Brownie: The brownie layer should remain fudgy for the best texture.
- Spread Batter Gently: Use a spatula to spread the butter cake batter evenly over the brownie layer to avoid mixing the two layers.
- Use High-Quality Chocolate: The rich flavor of the brownie comes from the chocolate, so use a good-quality dark chocolate.
This Brownie Butter Cake is the best of both worlds: rich, chocolatey brownie and buttery vanilla cake in one irresistible dessert. Every bite is a heavenly combination of textures and flavors. Enjoy!