1. Preheat the oven to 350 degrees F. Grease a 9x13 inch baking dish.
2. Add the butter to a medium pot set over medium heat. Allow the butter to brown lightly until it smells toasted, about 2-3 minutes. Stir often. Remove from the heat and stir in 1/2 cup peanut butter, the brown sugar, and sugar. Let this cool until no longer hot, about 5 minutes. Add the eggs, and vanilla. Add the flour and baking powder. Transfer the dough to the freezer and chill 5 minutes or until the dough is no longer warm to the touch. Stir in the chocolate chips.
3. Spread 1/2 the dough out into the prepared dish. Dollop and then gently swirl the remaining 1/4 cup peanut butter into the dough. Add the remaining dough over top, don't worry if it does not fully cover the peanut butter. Arrange the pretzels over top the dough, gently pressing to adhere. Transfer to the oven and bake for 22-25 minutes, just until set in the center. Remove from the oven and drizzle with melted milk chocolate and sprinkle with sea salt (if desired). Let cool. Cut into bars. Store for up to 5 days in an airtight container.
Recipe from Half Baked Harvest