Sheet Pan Mac n' Cheese

Bring a large pot of water to a boil. Add Kosher Salt (1 Tbsp) . Boil Elbow Macaroni (13 oz) for about 5 minutes, or for 2 minutes less than the box's suggested al dente time. Drain. Do not rinse. Set aside.

In the same large pot, melt Unsalted Butter (4 Tbsp) over medium-high heat. Add All-Purpose Flour (4 Tbsp) , whisking constantly for about a minute.

Add Whole Milk (2 cups) and Water (2 cups) , whisking to remove any of the flour-butter mixture from bottom of pan.

Bring to boil, then reduce heat and gently simmer. Add Kosher Salt (1 tsp) and Freshly Ground Black Pepper (to taste) . Simmer until mixture begins to thicken, about 20 minutes. The mixture will not get super thick, but it will coat the back of a spoon, and if you run your finger through the coating, the trail should stay. Remove from heat.

Meanwhile, melt the remaining Unsalted Butter (4 Tbsp) on a stovetop or in microwave. Pulse Bread (6 oz) in food processor to make crumbs. Measure 3 cups and place in a large bowl. Add Fresh Parsley (1 bunch) and Garlic (2 cloves) to food processor. Pulse until fine, then add to bowl with breadcrumbs. Season with Kosher Salt (1/4 tsp) . Pour melted butter over top and mix with spatula until combined.

In a large bowl, toss macaroni with Parmigiano-Reggiano (1 1/2 cups) — it's ok if the noodles are sticking together; they will separate once the béchamel is poured over top. Pour the béchamel over top and stir to mix.

Distribute Fresh Mozzarella Cheese Ball (1 cup) over the top.