Preheat oven to 350 degrees F and grease a 9 x 13 inch baking dish with non-stick spray.
Boil peeled and cubed potatoes in a 2-quart pot for about 7 minutes until tender but not mushy. Drain and place in the baking dish.
Brown kielbasa pieces in a frying pan with olive oil over medium heat for about 5 minutes, then add to the baking dish.
In the same frying pan with leftover oil, cook flour and butter over medium-low heat until the raw flour taste disappears.
Add minced garlic, milk, heavy cream, ground cumin, garlic powder, salt, pepper, and cheddar cheese soup; stir and simmer until thickened, about 3-4 minutes.
Stir in shredded cheddar cheese then remove the sauce from heat.
Pour the cheese sauce over the potatoes and kielbasa, tossing to coat evenly.
Bake in the preheated oven for 30 minutes until bubbling and golden.