Preheat oven to 350 degrees and line a cupcake pan with cupcake liners; set aside.
Cook bacon to your liking - either in a pan over medium heat or in a 400-degree oven for 15-20 minutes on a rimmed bacon sheet lined with parchment paper. Once cooked, drain on paper towels. Save excess grease from pan.
To make cupcakes, cream together butter and sugars. Add eggs and vanilla and mix, scraping down sides of bowl as necessary.
Mix dry ingredients (flour, baking powder and salt) in a small bowl.
With mixer on low-speed alternate adding dry ingredients and milk, starting and ending with dry ingredients - dry ingredients, milk, dry ingredients, milk then dry ingredients. Do not over-mix.
Lastly, stir in bacon grease.
Fill cupcake liners about half full and bake for 17 minutes. Let cool.
While cupcakes are cooling prepare frosting by creaming together butter and brown sugar for 5 minutes or until brown sugar has dissolved. Add confectioners' sugar, vanilla and 2 tablespoons of milk and mix until smooth. If frosting seems too dry, add a little more milk.
Next, chop up bacon and mix half of it it with half cup of the caramel sauce. Cut small holes in the center of each cupcake and fill with bacon caramel sauce.
Lastly, pipe cupcakes with frosting and garnish with caramel sauce and the rest of the bacon bits.