Carefully separate the Oreo® Chocolate Sandwich Cookies (20), scraping the filling into a bowl then tossing the chocolate cookies into a food processor, breaking the cookies up slightly.
Once all the cookies are in the processor, process into fine crumbs.
In a heavy-bottomed sauce pot, bring Water (1 cup), Butter (3 tablespoon), Brown Sugar (2 tablespoon) and Salt (1/4 teaspoon) to a boil.
In a mixing bowl, whisk together All-Purpose Flour (1 cup), 2 tablespoons Oreo cookie crumbs, and Ground Cinnamon (1 1/2 teaspoon). Once the water mixture has come to a boil, remove from the heat and mix in the flour mixture. Keep mixing until incorporated.
Add the Egg (2) and Vanilla Extract (1 teaspoon) and mix until a dough forms.
Line two baking sheets with parchment or wax paper. Fit a pastry bag with a large star-shaped piping tip and fill the bag with the churro dough.
Pipe the dough into 3-inch circles, starting at the center of the circle and working outward in a spiral pattern. You should be able to make 10-12 large churros from one batch.
Place baking sheet in the freezer for at least 10 minutes to set and chill the dough.
Meanwhile, heat up the Vegetable Oil (as needed) for frying. Add oil to a large skillet or deep fryer so that it's at least 2 inches deep. Heat the oil to 350 degrees F (180 degrees C). Line a separate baking sheet with several layers of paper towels.
In a medium-sized bowl, mix together Granulated Sugar (1/2 cup) with the remaining Oreo cookie crumbs.
Fry 1-2 churros at a time, turning them over occasionally so they brown evenly. When finished they will be slightly puffed. Transfer to the paper-towel-lined baking sheet using a slotted spoon or spatula to let the oil drain.
Quickly toss them in the sugar mixture while they are still hot. Continue working in small batches until all of the churros are fried.
Using a hand mixer or a stand-up mixer, whip Heavy Cream (1/2 cup) until stiff peaks are formed. Gently fold in the Oreo filling, being careful not to overmix. Place into a bowl and serve a dollop of whipped cream with each churro.