Cook the macaroni according to the package instructions, minus 2 minutes, for very al dente. Drain and set aside.
In a large pot over medium heat, melt the butter. Pour in the evaporated and whole milk and whisk to combine. Add the lager, Dijon mustard, Worcestershire sauce, garlic powder, onion powder, and smoked paprika. Continue whisking until the mixture thickens slightly.
Reduce the heat to low. Toss the shredded cheeses in the cornstarch to coat. Gradually add the shredded cheddar and Gruyère cheese to the sauce, stirring until the cheese is melted and the sauce is smooth. Season with the salt and black pepper. Add the cooked macaroni to the cheese sauce, stirring until the pasta is evenly coated and heated through. If desired, you can top the mac and cheese with panko breadcrumbs for a crunchy finish.