Preheat your oven to 350°F (175°C).
Cook the pasta according to package directions until just al dente.
Drain well and set aside. 2.
While the pasta cooks, melt the butter in a large saucepan over medium heat.
Add the minced garlic and cook, stirring constantly, for about 30 seconds until fragrant.
Whisk in the flour to form a smooth paste and cook for one minute. 3. Gradually pour in the milk, whisking continuously to prevent lumps.
Continue to cook and stir until the sauce thickens and begins to bubble. 4.
Reduce the heat to low. Gradually add the shredded Port du Salut (or Monterey Jack) and American cheese, stirring gently until the cheese is completely melted and the sauce is velvety smooth.
Remove the saucepan from the heat. 5.
Stir the cooked pasta and 2 tablespoons (30 ml / 1 fl oz) of fresh oregano (or 1 teaspoon dried) into the cheese sauce, mixing until every piece of pasta is generously coated. 6.
Transfer the mixture to an ungreased 1. 5 to 2-quart casserole dish.
Sprinkle the bread crumbs evenly over the top. 7.
Bake, uncovered, for 25 minutes, or until the sauce is bubbly and the topping is golden brown.
Let the casserole stand for 10 minutes before serving. This allows the sauce to set up perfectly.
Garnish with additional fresh oregano, if desired.
Remove the saucepan from the heat *before* stirring in the cheese. This gentle, residual heat will melt it perfectly without causing the sauce to break or become oily.
