Place dried porcini in a bowl with 1 cup hot water and soak for 20 minutes; remove mushrooms and chop, reserving the liquid through a fine-mesh strainer.
Heat olive oil in a large Dutch oven over medium-high heat.
Add chopped cremini mushrooms and cook undisturbed for 5 minutes, then stir and continue cooking until browned and moisture has evaporated.
Add diced onion, carrots, and celery to the pot and sauté for 8 minutes until vegetables are softened.
Stir in garlic, tomato paste, thyme, and red pepper flakes; cook for 2 minutes until the tomato paste is fragrant and deep red.
Pour in the red wine to deglaze the pan, scraping the browned bits from the bottom.
Add the reserved mushroom soaking liquid and the chopped porcini mushrooms.
Reduce heat to low and simmer for 25-30 minutes until the sauce has thickened and flavors are concentrated.
Season with salt and black pepper before serving.