Cook pasta in boiling salted water until al dente. Drain.
Heat milk and cream in a pot, don't let it boil.
Melt butter in a large pot. Add flour and whisk on low heat for 2-3 minutes.
Add hot milk/cream while whisking. Cook until thickened, 3-4 minutes.
Remove from heat. Mix in cheeses, salt, nutmeg, paprika, and pepper.
Toast breadcrumbs in butter with parmesan, salt, and pepper.
Mix cheese sauce with pasta. Transfer to baking dish. Top with cheddar, parmesan, and breadcrumbs.
Bake at 375F for about 35 minutes.