Cook your box of pasta according to the directions on the box for al dente pasta. Before draining, reserve a good size mug of that wonderful pasta water. Then drain and set aside.
Slice your beef smoked sausage on the diagonal, about 1/4 inch thick. Add the sliced sausage to a large sauté pan, and cook over high heat, tossing frequently until the sausage browns a little on each side. Remove the sausage from the pan and set aside.
In the same sauté pan, melt the butter over medium high heat. Add the minced garlic and cook for just one minute.
Whisk in the half and half and heavy cream. Continue to whisk as it comes to a simmer.
Once the mixture is simmering, add in all three cheeses, the Cajun seasoning and the black pepper. Continue to whisk until the sauce is smooth and creamy. Whisk in 1/2 cup of the reserved pasta water, then stir in the sausage and turn off the heat.
Pour the sauce with sausage over the drained noodles and toss it all together. Add additional pasta water by little splashes till the sauce is the perfect consistency.
Toss in the peas or serve on the side for the non-pea lovers in your fam. I like to garnish with a little bit of the creamy melt mozzarella over the top of each plate.