Béchamel sauce is the sauce that makes everything delicious. You can turn the most basic dish into something fantastic with an extra 10 minutes and a few ingredients that I know you have on hand. Béchamel sauce is sometimes called cream sauce or white sauce. Melt 2 Tablespoons of butter (I only use real butter and you should too) in a large skillet over medium heat. Add 2 Tablespoons flour and stir it into the butter. Allow the flour to cook out. This just takes a minute until it gets all bubbly and thick. This is called a Roux - wow look at me all fancy and speaking French. Don't over-cook your roux. It should not turn brown. I also add salt and pepper at this point. Maybe a teaspoon of both. You can use white pepper if you want to keep your sauce white.
After the flour has cooked a little, add 2 cups milk. and whisk to combine. Continue cooking on medium heat until it thickens. This next part is rocket science. Pay careful attention. If you want a thinner sauce add more milk.
After you make this a few times you'll never measure any of these things. You will know what it should look like and what it needs.
Taste it and add more salt and pepper if needed. Now add a sprinkle of nutmeg. Don't think I don't know what I'm talking about. Just try it and taste it again (with a clean spoon please - no double dipping here.) The nutmeg takes it from homemade to pro doesn't it!?! Now you can use this beautiful Béchamel sauce with your vegetables like I did here for New Potatoes and Peas in Cream Sauce.
Or you can throw in some grated cheese to make au gratin potatoes or homemade Mac-n-cheese. Or start the whole process with pan drippings from your meat and you've got a yummy country gravy.
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Béchamel sauce is one of the "4 Mother Sauces" in the cooking world. I consider it THEE mother sauce.