1. Preheat the oven to 325 degrees F. Butter a 2 1/2-quart baking dish. Bring a large pot of salted water to a boil over medium heat. Add the penne and cook, until just al dente, about 5 minutes. Drain and transfer to a large bowl. Add the havarti, gouda, and fontina cheeses and 1 tablespoon butter to the hot pasta and stir gently until cheeses begin to melt.

2. In a medium bowl, whisk the egg, evaporated milk, paprika, half the garlic, 1/2 teaspoon salt and pepper. Stir the egg mixture into the macaroni pasta. Transfer to the prepared baking dish; bake covered for 10 minutes.

3. Meanwhile, pulse the bread in a food processor with the olive oil, remaining garlic, and 1/4 teaspoon each salt and pepper; stir in the thyme leaves.

4. Uncover the casserole, sprinkle the pasta with the breadcrumb mixture, and bake until bubbly and golden brown, about 15 minutes more. Serve immediately.