Alex's Gluten-Free Brownies

These were incredible and she left me the recipe, so I'm taking the liberty of posting it here:

Ingredients:

• 1/2 cup butter
• 1/4 cup cocoa powder
• 1 cup brown sugar, packed
• 1 tsp. vanilla
• 2 large eggs
• 1/4 cup cornstarch
• 1/2 tsp. salt
• 1 cup dark chocolate (chunks or chips)

Directions: Preheat the oven to 350 F. Melt butter and cocoa powder in a bowl in the microwave. Add brown sugar, vanilla, and eggs and mix thoroughly. Mix in cornstarch and salt. Add dark chocolate and stir. Pour into a well-greased 8x8 pan and bake for 35 minutes or until a fork comes out clean.