Preheat oven to 400°F. Place fries onto a baking sheet and bake according to package directions.
Place a medium sauce pot over medium-high heat, add EVOO. Cook bacon until it is slightly browned and crispy. Remove half of the bacon from the pot, and set aside.
In a small bowl, mix the cornstarch and water together with your fingers until it reaches a heavy cream-like consistency. Add the garlic and onion to the pot with the remaining bacon and cook for 3-4 minutes. Slowly add the beer or stock. Bring up to a boil and cook for 2-3 minutes.