Bring Chianti and dried porcinis to a simmer in a medium pot set over medium-high heat. Cook for 5 minutes, then take the pot off the heat and cover. Let steep for 30 minutes, then scoop out the porcinis with a slotted spoon and reserve. Return the pot with the wine over medium-high heat and cook until reduced to 3 – 4 tablespoons of liquid. Chop the porcinis and set aside along with the reduced wine.
Warm olive oil and butter in a large, heavy-bottomed pot over medium heat. Once you see the oil shimmering, add the chopped onion, carrot and celery, and sauté for 3 minutes, stirring occasionally. Add the minced garlic, a pinch of red pepper flake, and the cremini mushrooms, then continue to sauté until vegetables are soft but not brown, stirring occasionally.
Add crushed tomato, tomato paste, water, bay, thyme, sugar, reserved chopped porcini, reduced wine, a few pinches of kosher salt and several turns of freshly ground black pepper, stirring to combine. Bring sauce to a boil, reduce heat to low then simmer, partially covered, for 1 hour.
To finish the sauce, stir in chopped parsley and basil. Season to taste with additional kosher salt and freshly ground black pepper.
Serve this sauce with your favorite pasta. I like to add two or three sizable spoonfuls of sauce to freshly drained spaghetti, tossing to coat. This will ensure that the spaghetti absorbs the flavor of the sauce. Place a mound of spaghetti on a plate then top with extra sauce (I like it saucy :)), chopped parsley and/or basil, grated Parmesan cheese and freshly ground black pepper.