Preheat the oven to 350° F. Line a 9x9 inch square pan with parchment paper.
Add the butter to a pot set over medium heat. Allow the butter to brown lightly until it smells toasted, 2-3 minutes. Remove from the heat. Mix in the mini chocolate chips until all are melted. Stir in the vanilla and instant coffee.
In a bowl, whisk the eggs for 1 minute until bubbly on top. Add the melted chocolate and powdered sugar, whisking until smooth, 1-2 minutes. Add the flour, cocoa powder, baking powder, and salt. Stir until just combined. Stir in the chocolate chunks.
Spread the batter into the prepared pan. Bake for 28-30 minutes or until the brownies are just set and crinkly on top. Sprinkle with flaked sea salt if desired. Enjoy!
