Add the dried Porcini mushrooms in a bowl and cover with boiling water. Let it sit for 10-20 minutes or until the mushrooms are fully rehydrated.
Bring a large pot of salted water to boil.
Finely chop the onion and add it in a non-stick pan with the cubed bacon. Turn on the heat to medium and fry for 2-3 minutes. The bacon fat should be enough to sauté the onion, but you can add a drizzle of oil if necessary.
Meanwhile, chop all the mushrooms and then add them to the pan. Add also the tomato paste to caramelize. Cook for 4-5 minutes. All the ingredients should caramelize together but not burn. Regulate the heat accordingly.
Toss the pasta in the boiling water and cook according to the package instructions. Drain it 1-2 minutes before it’s ready to finish cooking in the sauce.
Add the cream to the sauce and a few tablespoons of the Porcini water (filter it if necessary). Turn down the heat to low and simmer for 5-10 minutes.
Drain the cooked al dente pasta and add it to the pan with the sauce to finish cooking and absorb all flavors. Add more Porcini water if necessary.
Serve with freshly chopped parsley on top. You can also add some Parmesan cheese and freshly grated black pepper to serve.
Notes
You can store leftovers in an airtight container in the fridge for up to 3 days or in the freezer for up to 3 months.Reheat in the microwave or in a pan on the stove, adding a little bit of water or milk to make the sauce creamy again.