Pretzel Crust

1. Preheat oven to 350F/180C and line an 8-inch square pan with foil so that it hangs over each side. 
2. In a small bowl combine the crushed pretzels, brown sugar, baking soda, and flour. Mix in melted butter so everything is evenly moistened. Place into prepared pan and use the palm of your hand to pack tightly. Bake for 5-8 minutes, until lightly golden brown. Prepare brownie batter while the crust is baking.

Brownies

1. Preheat your oven to 350F and line a 9X9 or 8X8 square pan with foil and grease heavily.
2. In a large pot add the water, butter, sugar and cocoa powder. Cook on medium heat for 2-3 minutes until it is all combined together, the mixture will look weird and not liquidy enough, that is fine. Then add the oil and vanilla extract. Cook on low an additional minute and mix to combine everything.
3. Take off of heat, let sit for 5 minutes then add the egg and egg yolk. Whisk to combine.
4. Add the baking soda, salt, cornstarch and mix to combine. Gently add the flour by using a spatula to fold in until just combined, just before there are no flour streaks add your chocolate chunks/ chips. Do not over mix, this will affect the end product. Gently press in the chopped piece of peanut butter cups.
5. Pour into prepared pan and bake 25-35 minutes. Everyone’s oven is different, for me, the brownies always bake within 29-31 minutes, but I would start checking at 25 minutes for your oven. Don't overbake the brownies. You want a toothpick in the center to come out with moist crumbs, not completely dry. Place the pan on a wire rack to cool completely before cutting. Cutting the crust will be messy. Store in an air-tight container on the counter for up to 4 days.