Bring 2/3 cup water to a gentle boil. Remove from heat, add dried mushrooms, and simmer for 20 min. Strain and set aside mushroom stock.
Chop rehydrated mushrooms. * Melt 2 tablespoons of the butter and 1 tbsp olive oil in a pan set over medium-high heat. Add shallots and cook until translucent, about 1-2 minutes. * Add mushrooms (cremini and rehydrated) in an even layer; do not stir. Season with salt and pepper. Let cook for 2-3 minutes, flip and cook another 2-3 min. *
Add garlic, cook 1-2 min. * Remove mushrooms from the pan and add 1/2 cup of the mushroom stock to the pan, scraping the browned bits. Add red wine. * Boil until the liquid has reduced by half. While whisking, add flour and whisk for 1-2 min until thickened. * Turn the heat down to low, and add mushrooms back. Let simmer for 10 min. * Serve over polenta.
