Heat 2 tablespoosn olive oil in a large skillet, add sliced mushrooms and green bell pepper. Add just a pinch of salt. Cook on high heat for about 5 minutes, stirring. Reduce heat to medium-low and continue cooking mushrooms and bell pepper, covered for about 15 minutes, occasionally stirring.
Cook pasta according to package instructions. Drain.
Add heavy cream, milk, Parmesan cheese and ¼ teaspoon salt to the mushroom-bell-peper mixture on medium-low heat and mix. Add pasta to the creamy sauce, stir to coat on low heat for about 5-10 minutes until Parmesan cheese melts and starts to coat pasta as well. Season with salt and pepper, to taste.
Serve on warm plates (warmed in the oven). Garnish with chopped cilantro, if desired.