Preheat oven to 350ºF. Line an 8x8 inch pan with parchment paper or lightly grease it
Melt butter and chocolate: In a microwave safe bowl, melt the butter and ½ cup chocolate chips in 20-30 second intervals, stirring until smooth. Let cool slightly
Mix wet ingredients: stir in both sugars then beat in eggs and vanilla until mixture is glossy and slightly thickened
Add dry ingredients: Sift in the cocoa powder, salt, baking powder and gluten free flour. Stir just until no dry streaks remain
Pour and smooth the batter into the prepared pan
Bake for 22-26 minutes or until a toothpick inserted comes out with moist crumbs (not wet batter)
Cool completely before cutting—chill them for extra fudginess if desired!
