Heat oven to 350 degrees. Cook pasta according to package directions.
In a medium saucepan, bring the 2 cups of milk and half & half to just below a simmer, about 185 degrees.
Add cheeses, white pepper and salt, whisking continuously. Bring to a simmer.
In a separate small bowl, combine corn starch and ¼ cup milk. Add ¼ of cheese mixture into starch mixture. Add starch mixture into saucepan of cheese sauce.
Combine pasta and cheese mixture. Pour into casserole dish.
Bake 15 minutes. Optional: Sprinkle additional MontAmoré cheese on top and allow to melt. Let sit a few minutes before serving.