Sheet Pan Mac N’ Cheese

Steps

1. 1Preheat oven to 425°F.
2. 2Bring a large pot of water to a boil. Add a tablespoon of kosher salt. Boil macaroni for about 5 minutes or for 2 minutes less than the box’s suggested al dente time. (For example, my macaroni box said ‘al dente perfection’ in 7 to 9 minutes. I boiled mine for 5.) Drain. Do not rinse. Set aside.
3. 3In the same large pot, melt 4 tablespoons of butter over medium-high heat. Add flour, whisking constantly for about a minute. Add milk and water, whisking to remove any of the flour-butter mixture from bottom of pan. Bring to boil, then reduce heat and gently simmer. Add 1 1/4 teaspoons kosher salt and pepper to taste. Simmer until mixture begins to thicken, about 20 minutes. Note: 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 — see photo. Remove from the heat.
4. 4Meanwhile, melt remaining 4 tablespoons of butter stovetop or in microwave. Pulse bread in food processor to make crumbs. Measure 3 cups and place in a mixing bowl. Add parsley (it’s ok if the tender stems are included — use the top 3/4 or so of the bunch) and garlic to food processor. Pulse until fine, then add to bowl with breadcrumbs. Season with 1/4 teaspoon kosher salt. Pour butter over top and mix with spatula until combined.
5. 5In a large mixing bowl, toss macaroni with grated Parmigiano Reggiano — 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.
6. 6Line a jelly roll pan with a sheet of parchment paper. Spread macaroni mixture over top. Distribute mozzarella cubes over top. Scatter breadcrumb mixture evenly over top.
7. 7Bake for 25 to 30 minutes, or until top is golden and the macaroni is bubbling. Let sit 10 minutes before serving.