Line an 8” x 8” baking pan with parchment paper and lightly spray with non-stick cooking spray. Leave the parchment paper slightly higher than the edges of the pan so the brownies can be easily lifted out when cool.
In a large bowl, melt butter and semi-sweet Baker’s chocolate in the microwave. Start with 1-minute on high power then remove bowl from microwave and stir well. If the chocolate is not yet melted, continue to heat on 30-second intervals (stirring after each 30 seconds) until the chocolate is melted. This mixture should be melted but not really hot.
Stir the granulated sugar and brown sugar into the melted mixture until smooth.
Stir the eggs (1 at a time) into the batter until each egg is fully mixed into the brownie batter.
Stir the cocoa powder, vanilla extract and salt into the brownie batter until smooth.
Pour the brownie batter evenly into the prepared baking pan.
Bake at 350°F for 21-23 minutes. Gently shake the baking pan to check for doneness. The middle of the brownies should no longer be jiggling when the brownies are fully cooked. Do not overcook the brownies or they will become dry instead of being chewy and fudgy.
Let the brownies cool completely before removing from the pan and slicing.
Notes
Flourless brownies can be stored (in a sealed food-safe container) at room temperature for up to 3 days or in the refrigerator for up to a week.
Flourless brownies can be frozen for up to 2 months. Allow brownies to cool completely before placing in a sealed food-safe container for the freezer. Place a piece of wax paper between slices so they don’t stick together once frozen. Bring flourless brownies back to room temperature before serving.