Preheat your oven to 375°F (190°C) and grease a muffin tin or line it with paper liners.
In a large mixing bowl, combine the flour, baking powder, baking soda, salt, black pepper, garlic powder, and onion powder. Whisk together until well mixed.
Fold in the shredded cheddar cheese, cooked sausage, and chopped green onions until evenly distributed.
In a separate bowl, whisk together the milk, vegetable oil, and eggs until well combined.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Be careful not to overmix; a few lumps are okay.
Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full.
Bake for 18-20 minutes, or until the muffins are golden brown and a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.