Why bother doing this on top of the stove if you have a microwave? I like this method as it is so much easier and quite frankly, it would be almost impossible to scorch it!
4 Tbsp butter
3 Tbsp flour
Bay Leaf, piece of onion, 2 whole cloves (opt.) or pinch of nutmeg (opt.)
2 cups milk
Salt & freshly ground black pepper to taste
Place the butter in a glass bowl; cover with a piece of wax paper and microwave on level 6 or 8 until melted; approximately 30 seconds to a minute. Whisk in the flour; return mixture to the microwave. Microwave for 30 seconds to a minute, until bubbly; slowly whisk in the milk. Add the bay leaf, onion, cloves or nutmeg if using. Microwave, in 1 minute increments; whisking after each minute until bubbling & thickened. Remove from microwave and now you have a béchamel. If sauce is a bit too thick, simply whisk in some additional milk.