Preheat the oven to 350°F (175°C) and spray an 8x8-inch baking dish with nonstick spray.
Cook the elbow macaroni in a large pot of boiling salted water according to package directions until al dente; drain and transfer to a large mixing bowl.
Warm the 2 cups of milk in a small saucepan over medium heat until hot but not boiling, then reduce heat to low to keep warm.
In a medium saucepan, melt 1/4 cup (1/2 stick) butter over low heat. Whisk in 1/4 cup all-purpose flour and cook, stirring constantly, for about 3 minutes until smooth and bubbly.
Gradually whisk the warm milk into the roux, increasing heat to medium-high and stirring frequently until the sauce comes to a gentle boil; then reduce heat to low.
Stir in 1/2 teaspoon salt, 1/2 teaspoon Tabasco, and freshly ground black pepper to taste. Add 1/2 cup heavy whipping cream and simmer on low for 3–4 minutes, stirring occasionally.
Add 12 ounces of the shredded cheddar to the sauce and stir constantly until melted and smooth.
Pour the cheese sauce over the drained pasta and stir until the pasta is evenly coated.
Transfer the sauced pasta to the prepared baking dish, sprinkle the remaining 4 ounces of shredded cheddar over the top, and bake for 20–30 minutes until bubbly.
If desired, broil for 2–3 minutes to brown the top, watching closely to avoid burning. Let rest a few minutes before serving.
