Cook macaroni in a pot of salted boiling water until just tender. Drain.
In a large saucepan, melt the butter, then whisk in the flour until smooth.
Whisk in milk, continue whisking until thickened, then season with salt and pepper as desired.
Stir in 1½ cups of the cheese, reserving ½ cup for the topping. Stir until cheese is melted in.
Preheat your oven to 180° C (350° F), get out and grease with butter or cooking spray, a 7x11 inch baking pan.
Place the drained macaroni in the pan and spread out evenly.
Pour cheese sauce evenly over the top.
Salt the tomato slices and arrange on top, pushing he side of each slice slightly into the macaroni.
Top with remaining cheese.
Bake for 30 minutes or until hot and bubbly.
Sprinkle with paprika, serve and enjoy.