Preheat the oven to 350°F. Lightly grease an 8x8 pan and line with parchment paper.

In a medium microwave-safe bowl, melt the 4 tbsp butter and set aside.

Using a food processor, blend up brown sugar and pretzels until fine crumbs. Combine crumbs with the melted butter and press into the pan evenly. Bake for 6-8 minutes until golden brown. Set aside while making brownie batter.

In a small microwave-safe bowl, melt chocolate chips in 15 second increments while stirring between increments until fully melted.

Melt butter in a medium microwave-safe mixing bowl. Mix in both sugars, then add vanilla extract and eggs.

Fold in melted chocolate chips. Mix in flour, salt, and cocoa powder until just combined. Pour batter onto the baked pretzel crust and spread to smooth the top evenly.

Bake for 28-35 minutes, check them after 28 minutes frequently, secret to fudgy brownies is to undercook them so that they continue to slightly bake while cooling but not too much. When it's time to take them out of the oven, they'll jiggle ever so slightly in the middle and cooked around the edges.

In a medium heavy-bottom, light-colored saucepan, let the sugar and water cook until it forms into a honey/amber color. Turn off the heat and add butter, but be cautious because it will be bubbling! Mix with a wooden spoon until butter is melted. Slowly stir in heavy cream, it will start to come together as a silky, amber-colored, sauce. Transfer to a heat-safe bowl with a lid and place in the refrigerator until room temperature.

Drizzle on top of brownies once cooled.