Season with salt and pepper and pour sausage mixture over pasta, add parsley and
more pasta water if it seems dry.
Add the pesto, mascarpone and 3 - 4 tbsp of the reserved pasta water, then stir until the mascarpone has melted, adding a
splash more pasta water if the sauce needs thinning.
Sprinkle with the Parmigiano - Reggiano and add
more pasta water to desired sauce consistency.
Add
more pasta water to thin sauce to desired consistency.
Add
more pasta water a little at a time if the sauce is too thick.
If mixture appears dry, add
some more pasta water (I will usually add another ladle or so of pasta water; increase the heat and mix the whole thing together for a few minutes until the water is almost evaporated).
If the sauce is too thick, add
more pasta water.
Reduce heat to LOW and simmer until liquids have cooked down into a light, creamy sauce; stirring as needed (about 5 min); add
more pasta water, if needed to adjust consistency.
You want it to be glossy; if it looks dry or clumpy, add
more pasta water.
(Add
more pasta water if sauce seems dry.)