Cook the pasta following the instructions on the package.
Stir-fry jalapenos and onions in the butter until softened, about 5 minutes.
Whisk in the flour and continue to cook for 4-5 minutes, stirring often.
Pour in the heavy cream and milk and whisk together. Add cheese, 1 cup at a time, until melted, stirring well after each addition. Let cook for 10-15 minutes, stirring often.
Mix cheese sauce with pasta. Add beans on top (or mix them in) and sprinkle parmesan over it.