Melt butter in medium saucepan. Saute diced jalapenos in the butter for 5 minutes or until tender (do not brown). Add flour and stir mixture for 2 minutes. Gradually add milk until mixture is smooth and creamy. Simmer on low for 15-20 minutes. While sauce is simmering cook macaroni until tender (8-10 minutes) then drain and rinse. Add shredded cheese to the sauce and stir until melted. Add the sauce to the drained macaroni and mix well. Heat until bubbly on the stove or place in a buttered casserole, top with bread crumbs and bake in a 350 degree oven until it bubbles. Note; You may need to add additional milk to the sauce if it seems too thick. As always, adjust the amount of jalapenos and type of cheese to suit your taste.