Place the 12 oz. bottle of beer in a large saucepan. Place over high and and stir constantly. You want to reduce it to 2 tablespoons of liquid. It will take 17-18 minutes. Remove from the heat and let cool completely.
Preheat oven to 350 degrees. Line a baking sheet with parchment paper.
In a large mixing bowl, add in the vegetable oil, granulated and brown sugar. Mix on medium with a hand mixer until incorporated.
Add in the egg and mix on medium until incorporated.
Add in the flour, cocoa powder and salt. Mix on low until all the flour is incorporated.
Add in the crushed pretzel pieces and caramel bits. Press the bits in with a spatula.
Scoop the cookies out with a medium cookie scoop. Place on the baking sheet. They won't spread out.
Bake for about 16- 18 minutes until the cookie looks set and the edges are golden brown. It will be really hard to see the golden brown edges since it's a chocolate cookie.
Let the cookies cool for about 10 minutes before moving them from the baking pan to a cooling rack.
Notes
To store any leftover cookies, place in an air tight container or bag and keep at room temperature out of direct sunlight for up to 5 days.