Milk Chocolate Peanut Butter Truffle Brownies

1. Preheat the oven to 350° F. Line a 9x9 inch square pan with parchment paper.
2. In the microwave, melt together the butter and 1 cup chocolate chips (stirring at 30-second intervals) until melted and smooth. Stir in the sugar, Kahlúa (if using) vanilla, and instant coffee. 
3. In a small bowl whisk the eggs for 1 minute until bubbly on top. Stir the eggs into the chocolate mix. Add the flour, cocoa powder, baking powder, and salt. Stir until just combined. Stir in the remaining 1/2 cup chocolate chips. Evenly spread the mixture into the prepared baking pan. Bake for 28-30 minutes or until the brownies are just set. Let cool.
4. Meanwhile make the truffles. In a microwave-safe bowl, melt together the semi-sweet chocolate and cream until melted and smooth. Pour about half of the chocolate truffle/ganache over the brownies and smooth it out until it reaches the edge. Swirl in the peanut butter, then place the brownies in the freezer for 15 minutes to set. Once set, pour over the remaining truffle/ganache. Melt the remaining milk chocolate and drizzle it over the truffle layer. Allow the brownies to set at least one hour in the fridge or two hours at room temperature. Sprinkle with caramel brûlée, if desired. Cut into bars. 
5. To make the Caramel Brûlée. Line a baking sheet with parchment paper. In a medium pot, cook the sugar over medium heat, stirring occasionally with a heat-proof spatula until the sugar has melted and turns a golden caramel, about 8 minutes. Remove from the heat and carefully pour the caramel onto the prepared baking sheet. Spread in a thin, even layer and sprinkle with flaky sea salt. Let sit 5 minutes. Once hardened, crush the caramel into small pieces/shards with the back of a spoon.