Preheat the Oven to 350F.Cook the pasta as per the instructions in the packet. Cooking upto 90% is enough since more cooking will take place in the oven.
In a saucepan or microwave, warm the milk slightly with Bay leaf. Allow it to infuse for 5 min.
Meanwhile heat a non stick or heavy bottomed pan. Add the butter and melt it on medium heat.
Add the flour and whisk it well.
In 2-3 minutes you will notice that it starts foaming (with little bubbles on the surface) and getting a lightly toasty smell. Take care not to burn it/darken it.
Remove the bay leaf from the milk and add it along with this flour mixture and whisk well till it thickens in consistency, approx 5-6min.
Remove from heat and add all the cheeses to it. Mix it till it melts into one solid mass.
Now add the pasta to this mixture. Make sure you have drained the pasta well.
Do a taste test and season it if needed. Mix until well combined.
Pour it out onto a well greased baking dish.Sprinkle the top with bread crumbs
until it covers the top completely (you can also drizzle some olive oil on top or dot it with some butter to give it a nice red/brown color) and bake it in the oven for 30-40 min
till it starts bubbling and the top is browned. Its a good idea to place a foil or another oven proof dish to catch any spills from the dish when its bubbling.Scoop it on a plate and get ready for a heavenly experience.