01 -
Preheat oven to 350°F (175°C) and coat a 9x13-inch baking dish with cooking spray.
02 -
Boil peeled and cubed potatoes in salted water until just tender, approximately 7 minutes. Drain well and transfer potatoes to the prepared baking dish.
03 -
Heat olive oil in a large skillet over medium-high heat. Cook sliced kielbasa until well browned, about 5 minutes. Scatter kielbasa over the potatoes in the baking dish.
04 -
In the same skillet, melt butter over medium heat. Stir in the flour and cook, whisking, until the mixture is pale golden and no longer raw, about 1-2 minutes.
05 -
Add minced garlic to the roux and cook until fragrant, 30 seconds. Gradually whisk in 2% milk and heavy cream. Stir in ground cumin, garlic powder, salt, black pepper, and cheddar cheese soup, cooking until thickened, 3-4 minutes.
06 -
Remove skillet from heat. Add shredded sharp cheddar cheese and stir until the cheese is fully melted and the sauce is smooth.
07 -
Pour the cheese sauce evenly over the potato and kielbasa mixture in the baking dish. Bake until the top is golden and bubbling, about 30 minutes.
08 -
Let the casserole rest for 10 minutes before serving for best texture.