3 tablespoons chopped parsley
Clean mushrooms, keeping colors separate, and trim tough stems. (Save stems for stock.) Slice mushrooms about 1/8-inch thick.In a wide skillet, warm 2 tablespoons olive oil over medium high heat. Add onion, season with salt and pepper and cook, stirring, until onion has softened and browned, about 10 minutes. Remove from pan and set aside.
Add 1 more tablespoon oil and turn heat to high. Add brown mushrooms, season lightly and stir-fry until nicely colored, about 3 minutes. Lower heat to medium. Add thyme, sage, red pepper and tomato paste. Add tomatoes, stir well, and cook for 1 minute. Season again with salt and pepper. Sprinkle with 1 tablespoon flour, stir to incorporate and cook for 1 minute more. Stir in reserved onions.
Add 1 cup mushroom broth and stir until thickened, about 1 minute. Gradually add 1 more cup broth and cook for 2 minutes. Sauce should have gravy-like consistency; thin with more broth if necessary. Adjust seasoning. (May be prepared to this point several hours ahead and reheated.)
Just before serving, put butter and 1 tablespoon olive in wide skillet over medium high heat. When butter begins to brown, add chanterelles, season with salt and pepper, and sauté for about 2 minutes, until cooked through and beginning to brown. Add garlic and parsley, stir to coat and cook 1 minute more. Add chanterelles to brown mushroom mixture and transfer to a warm serving bowl. Accompany with polenta or pasta if you wish.