Using kitchen shears cut bacon to bite sized chunks and into a large skillet over medium high heat. Cook bacon until done.
Meanwhile, fill an 8 quart pot with water, cover and bring to a boil over high heat. Add a small handful of salt (2 tablespoons) to boiling water and cook pasta until al dente (about 7-9 minutes). Pour peas into boiling water 2 minutes before end of cook time.
Add flour to skillet and whisk to combine. Cook over medium heat for about 3-5 minutes stirring occasionally to cook out the flour-y taste. Add milk and whisk to combine. Add cheeses and stir.
Remove from heat, reserve ½ cup pasta water, and drain when done. Add pasta and peas to skillet and stir to combine. Add pasta water a little at a time until you have a perfect creamy consistency.