1 tablespoon (15 mL) vegetable oil
1 pound (450 g) elbow macaroni
8 tablespoons (120 mL) plus 1 tablespoon (15 mL) butter
3/4 cup (180 mL) Havarti cheese, shredded
3/4 cup (180 mL) mild cheddar cheese, shredded
3/4 cup (180 mL) sharp cheddar cheese, shredded
3/4 cup (180 mL) Monterey cheese, shredded
2 cups (500 mL) half-and-half
1 1/2 cup (375 mL) Velveeta, cut into small cubes
2 large eggs, lightly beaten
¼ teaspoon salt
1/8 teaspoon fresh ground black pepper
Preheat the oven to 350ºF (175ºC). Lightly butter a deep 2½-quart (2.8 L) casserole.
Bring a large pot of salted water to a boil over high heat. Add the oil, then the elbow macaroni, and cook until the macaroni is just tender, about 7 minutes. Do not overcook. Drain well and return to the cooking pot.
In a small saucepan, melt 8 tablespoons (120 mL) of butter. In a large bowl, mix the Havarti, mild and sharp cheddar, and Monterey Jack cheeses. Add the 8 tablespoons of melted butter to the macaroni. Stir in 1½ cups (375 mL) of the shredded cheese and the cubed Velveeta. Stir until the cheese has melted. Add the half-and-half, along with the eggs. Mix until combined. Season with salt and pepper. Transfer to the buttered casserole dish. Sprinkle with the remaining 1½ cups (375 mL) of shredded cheese and dot with the remaining tablespoon of butter.
Bake until golden and bubbling around the edges, about 25 minutes. Serve hot.