Place a large pot of salted water on the stove on medium-high heat & let come to a boil. Then cook pasta according to instructions on box. (I think it was 10 minutes for al dente.)
In the mean time, in a large saute pan cook the sausage, crumbling with a wooden spoon as you go. Once there is no more pink sausage place in a bowl and set aside for later. In the same pan add the minced garlic & saute in sausage juices for about 1 minute. Add the mushrooms and let cook down about 5-7 minutes.
Add the milk & chicken stock & bring to a simmer. Let simmer for about 5 minutes, add the half n half & bring back up to a low simmer. Add the slurry, stirring the entire time. Let the sauce come back to a simmer and thicken. Add back in the sausage, stirring to coat then the peppers.
Once the pasta is cooked to your liking, strain. Add half of the sausage & pepper sauce into a large serving bowl, add the strained pasta then the rest of the sauce over top. Pour the cheese over the pasta and toss to incorporate.