Cook the pasta according to the instructions on the box.
Grate the carrots and the mozzarella cheese.
Put the butter in a casserole and melt it.
Add the flour in the butter and stir.
Add the milk and let stir until it boil.
Lower the heat and add the ajvar relish sauce and the carrots in the sauce. Let it warm in the casserole for 1 more minute.
Serve the pasta and the sauce warm on a plate, and sprinkle the mozzarella cheese on top of the dish.