Lightly grease a 9-inch square baking dish.

Place potatoes in a pot of salted water. Bring to a boil and boil until just tender.

Drain well and place potatoes in the prepared baking dish.

Heat a large nonstick skillet over medium-high heat. Add olive oil and sausage, cooking until browned. Remove sausage and place in the baking dish with potatoes.

Wipe skillet clean and add butter. Melt over medium heat, then add flour and cook for 1 minute.

Gradually whisk in half-and-half, bring to a simmer, and add garlic powder.

Turn heat to low and add Velveeta. Stir until melted.

Add half the cheddar cheese and stir until melted. Remove from heat and season with salt and pepper to taste.

Pour cheese sauce over potatoes and sausage, then sprinkle the remaining cheese on top.

Bake in a 350 degree oven for 25 to 30 minutes.