Preheat the oven to 425 degrees F (220 degrees C). Spray a 9x13-inch casserole dish with cooking spray.

Bring a large pot of lightly salted water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally, until tender yet firm to the bite, about 8 minutes. Drain.

While the macaroni is cooking, slowly melt butter in a large pot over low heat. Stir in evaporated milk and pepper; cook until heated through.

Whisk eggs in a bowl until smooth. Whisk in about 1/2 cup of the hot evaporated milk mixture, 1 tablespoon at a time, until thoroughly incorporated. Whisk egg mixture back into the saucepan and continue to heat gently, whisking constantly, until milk mixture almost comes to a simmer and the sauce thickens.

Gently mix in cooked macaroni and salt until combined. Spoon 1/4 of the macaroni mixture in a layer into the bottom of the prepared casserole dish and top with 1 cup shredded Cheddar cheese. Repeat layers three more times, then sprinkle paprika over the casserole.

Bake in the preheated oven until bubbling, about 20 minutes.