Preheat oven to 350°. Cook pasta al dente per package directions. Rinse with cold water and set aside.

Cook the peppers over direct heat until skin is black and blistered (a gas cooktop flame or broiler works well). Place in a paper bag and let rest for 10 minutes. Peel the blistered skin under running water. Remove the stems and seeds, and chop to ¼ inch.

Melt 4 tbs of butter in a saucepan over medium heat. Add flour and cook for two minutes, whisking continually. Slowly add the milk and cream while whisking. Cook until the sauce thickens, about 10 minutes, stirring often. Remove from heat.