To a bowl, add warm water, then yeast and granulated sugar. Stir, then let sit so the yeast can activate and become frothy (approx. ten minutes).

In a separate, large bowl, stir together 3 cups of flour, brown sugar, and salt. Pour yeast mixture into flour mixture, along with canola oil, vanilla extract, and peanut butter. Stir and mix together until ingredients form a cohesive dough, adding additional flour by the tablespoonful as needed (see note). Mix in mini chocolate chips. Knead for a few minutes until dough is smooth (or use dough hook attachment on stand mixer) and forms a ball.

Spray another bowl with cooking spray and place dough in it, turning dough ball a few times so that it's evenly coated. Cover bowl snugly with plastic wrap and let dough rise for approx. one hour in a warm place.

Preheat oven to 400°F. Spray baking sheets with cooking spray and set aside. Portion out dough into sixteen evenly-sized sections. Roll each section into a long cylinder approximately 1/2" - 3/4" thick. Fold the middle of each pretzel rope in half and twist once or twice to create the twist shape.

Place pretzel twists on prepared baking sheets and press additional chocolate chips into top of pretzels. Bake 8-10 minutes, or until bottoms of pretzels have browned and tops have crisped. Let cool on wire rack.

Once pretzels have cooled, cream together butter, confectioners' sugar, vanilla extract, and milk for the icing. Transfer icing to a plastic bag and snip off the corner. Pipe icing in your preferred pattern over top of pretzels and let harden before serving (or don't!).