Cook bacon in a large skillet over medium-high heat until crisp, about 10 minutes. Drain the bacon slices on paper towels and crumble once cooled.

Preheat oven to 400 degrees F (200 degrees C). Coat 24 muffin cups with cooking spray.

Mix flour, Cheddar cheese, baking powder, garlic salt, and black pepper together in a large bowl.

Beat eggs, milk, and vegetable oil together in a small bowl; stir into flour mixture just until moistened. Gently fold bacon through the batter. Spoon batter into prepared muffin cups.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 15 to 20 minutes. Serve warm.