Creamy Pasta in white sauce

A few weeks back, the little girl went to a friend's birthday party and came back raving about the W.O.N.D.E.R.F.U.L creamy pasta that she ate there. The only help I got from her in helping me to figure out what made it so wonderful is that it was creamy and non spicy and that she loved it. Not one to miss out on a opportunity to feed her something that she likes, I too decided that I would make pasta for dinner.

What you need:
Pasta - any kind - 2 cups, cooked as per package instructions. (I used macaroni as the little girl is partial to it)
Mixed vegetables - of your choice - chopped into thin, long pieces and cooked. (I used carrots and beans, though the usual choices are broccoli and bell pepper)
Garlic - a few cloves
Celery - some, finely chopped
For the sauce:
Butter - 4 tsp
All purpose flour - 4 tsp
Milk - 1/2 litre - approx 3 cups
Onion - chopped fine
Black peppercorns - 5 or 6
Cloves - 5
Bay leaf - a small piece

To make sauce:
Melt the butter in a small saucepan. Add the flour to it and stir over a low flame to make a smooth paste. The colour of the flour should not change. Remove from heat and set aside.
Heat milk in a thick bottomed pan. Add half the chopped onion to it along with peppercorns, cloves, garlic and bay leaf. When the milk boils, add the flour paste to it. Whisk over a low flame. When the mixture thickens, remove from heat and strain.

Assembling the pasta:
Heat some butter in a pan. Saute the finely chopped onion, garlic and the cooked vegetables. Add the cooked pasta, pasta sauce and salt as required. Heat till the pasta is well coated with the sauce.
Garnish with finely chopped celery/parsley.
Serve hot with some crushed pepper sprinkled on top.

This is my first post for the Blogging Marathon under the theme "Cooking by the Alphabet".
Check out the Blogging Marathon page for the other Blogging Marathoners doing BM#15