Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish with butter or nonstick cooking spray.

Bring 4 quarts of heavily salted water to a rolling boil in a large stockpot over high heat.

Add 16 ounces of elbow macaroni to the boiling water and cook for 6 minutes, which is exactly 2 minutes less than the package directions for al dente.

Drain the cooked elbow macaroni thoroughly in a colander, shaking off excess water, and do not rinse the warm pasta with cold water.

Whisk together 1 cup of Thousand Island dressing, 1 cup of whole milk, 0.5 cup of heavy cream, 2 beaten large eggs, 0.5 teaspoon of garlic powder, 0.5 teaspoon of onion powder, 0.5 teaspoon of salt, and 0.25 teaspoon of black pepper in a large mixing bowl until fully combined.

Fold the warm drained macaroni into the dressing mixture, then stir in 2.5 cups of the shredded sharp yellow cheddar cheese until evenly mixed.

Transfer the macaroni mixture into the prepared 9x13-inch baking dish and smooth the surface into an even layer using a spatula.

Sprinkle the remaining 0.5 cup of shredded sharp yellow cheddar cheese evenly across the top layer of pasta.

Combine 1 cup of crushed Ritz crackers and 3 tablespoons of melted unsalted butter in a small bowl until the crumbs are uniformly coated, then scatter them over the cheese layer.

Cover the baking dish loosely with aluminum foil and bake at 350°F for 20 minutes.

Remove the aluminum foil and continue baking for 15 minutes, until the crumb top is golden brown and small bubbles form along the edges of the pan.

Remove the dish from the oven and let it rest at room temperature on a wire rack for 15 minutes before slicing and serving.