Preheat the oven to 350°F. Grease a 9x13 inch baking dish and set it aside.
Cook the gluten-free elbow macaroni according to the package instructions. Drain and set aside.
In a medium-sized saucepan, melt the lactose-free butter over medium heat.
Add the gluten-free flour and whisk until the mixture is smooth.
Gradually add the lactose-free milk, whisking constantly to prevent lumps from forming.
Add the salt, black pepper, paprika, and garlic powder to the saucepan and stir to combine.
Cook the mixture for 2-3 minutes or until it thickens and coats the back of a spoon.
Remove the saucepan from the heat and add the shredded lactose-free cheddar cheese and nutritional yeast flakes. Stir until the cheese is melted and the mixture is smooth.
Add the cooked gluten-free elbow macaroni to the cheese sauce and stir until it is evenly coated.
Pour the mac and cheese into the prepared baking dish and spread it out evenly.
Bake the mac and cheese for 20-25 minutes or until it is hot and bubbly.
Let the mac and cheese cool for a few minutes before serving.