Preheat your oven to 350°F (175°C). Line a large baking sheet with parchment paper.

1. In a medium saucepan, melt the butter over low heat. Remove from heat and stir in granulated sugar and brown sugar until fully combined.
2. Add eggs and vanilla extract, mixing until smooth.
3. In a separate bowl, whisk together flour, cocoa powder, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, stirring just until combined.
4. Spread the brownie batter evenly onto the prepared baking sheet to create a thin layer. Bake for 15–18 minutes, or until set. Let cool completely.
5. Once cooled, cut the brownie sheet in half to create two equal-sized layers. Spread softened ice cream over one half.
6. Carefully place the second brownie layer on top, pressing gently. Freeze for at least 2 hours, or until firm.
7. Cut into individual sandwich squares using a sharp knife. Serve immediately or return to freezer for later.