Preheat the oven to 375°F. Grease a muffin tin with cooking spray or line with muffin liners.
In a large bowl, whisk together the flour, baking powder, salt, and sugar.
In another bowl, combine the milk, eggs, and vegetable oil. Mix well.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Fold in the crumbled sausage, shredded cheddar cheese, black pepper, and garlic powder if using.
Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full.
Bake for 18-20 minutes or until a toothpick inserted in the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.