Cook pasta for 8-10 minutes in salted boiling water then drain and set aside.
While the pasta cooks cook the bacon in a skillet over medium heat until crisp then drain on paper towels and set aside.
Melt the butter in large pot over medium heat. When the foaming subsides add the flour and stir to combine. Continue to stir frequently until light golden brown, about 1-2 minutes.
Add milk and cream and whisk until well combined and there are no lumps. Bring to a low simmer and cook for 3-4 minutes until thickened, then add the shredded cheeses in batches 1-2 cups at a time, stirring until each batch is fully melted and smooth. Finally, stir in the cream cheese and season with the dry mustard, salt, and pepper.
Add your cooked pasta and bacon stir until combined.