Penne in Cheese Sauce

Ingredients : (serves 2) 150gms penne or other pasta 2tbs butter 2 1/2tbs all-purpose flour 2cups milk 1/3-1/2cup cheese (I used medium cheddar) 2 cloves garlic, finely chopped 1/2cup sweet corn kernels 1 big capsicum, cut into 1" strips 1 tomato, cut into 1" strip..