Classic Baked Macaroni and Cheese

Before I write, let me just say this recipe was originally FineCooking's. I tweaked it.
Last weekend, I made this wonderful Macaroni and Cheese for a girls' night party. Here's the recipe I promised you:

Classic Baked Macaroni and Cheese
Ingredients

• Kosher Salt
• 6 tbs. unsalted butter
• 1 medium onion, finely diced
• 6 tbs. all-purpose flour
• 1 tbs. Dijon mustard
• 1 quart whole milk, heated
• 1 large sprig fresh thyme, plus 1 tbs. chopped thyme leaves
• 1 bay leaf
• 8 oz. grated extra-sharp white Cheddar (the sharpest you can find)
• 4 oz. grated Monterey Jack
• 1/2 tsp. Worcestershire sauce
• 1/2 tsp. Tabasco sauce
• Freshly ground black pepper
• 1 lb. macaroni (elbow or something fun and small)
• 2 tbs. extra virgin olive oil, plus more for the baking dish
• 2 cups fresh breadcrumbs
• 1 1/2 oz. freshly grated Parmigiano-Reggiano

Directions

• Read the entire recipe before you start. Get the steps in your mind so that when it's time to start, you know what you are doing as you go.
• Heat the oven to 400 degrees.
• Boil your pasta in a big pot. (Pasta cooks better if you give it plenty of water and space to swim around in, but you won't kill the pasta totally if you only have a medium pot to boil these noodles in.) (Oh, and you can boil this earlier. You don't have to do it while you are compiling your white sauce. I don't know about you, but that's waaaaay too much multitasking for me.)

Compile your white sauce:

• Melt the butter. It should sizzle up a little then calm down.
• Throw in the onion and 1/2 tsp. salt and cook until the onion is softened.
• Now add the flour, and cook. Stir it, and cook the flour for about 1-2 minutes.
• Stir in the mustard.
• Add the milk. (Use a whisk for this step. Add the milk slowly until you whisk all the butter-flour lumps out. Be sure the milk is warmed because adding cold milk to hot butter-flour will make your butter-flour wonky.)
• Now add the bay leaf, thyme sprig, and another 1/2 tsp. salt. Let it come to a bare simmer.
• Cook this for 15 minutes to let the flavors get cozy with each other. Stir frequently. Don't burn the milk on the bottom of your pan.
• Pull out the herbs (bay leaf and thyme sprig).
• Add the cheeses. (Use a spoon for stirring during this part, because melty cheese is a devil to wash off a whisk!) Stir just until melted. (If you let it overcook with cheese in it, the cheese will get oily and yucky.)
• Add the Tobasco and Worcestershire. Season to taste with salt and pepper.

Take the sauce off the heat and gently mix in the cooked pasta.

Dump into a buttered/oiled oven-safe dish, and cover with bread-crumb topping.

Bake in oven for 15 minutes to get that bread-crumb topping crispy and wonderful.

Let the macaroni and cheese rest 5-10 minutes before serving, even though you will want to gobble it all right there right away!

Bread-Crumb Topping

• Toss the breadcrumbs (2 cups), Parmigiano (1 1/2 oz.), olive oil (2 tbs.), chopped thyme (1 tsp.), 1/2 tsp. salt, and 1/4 tsp. pepper all together.
• If you do this step beforehand, then you'll be ready to roll when your white sauce-cooked pasta is in the dish and ready to roll.