Heat 3 Tbsp of olive oil in a dutch oven or heavy bottomed pot. Add half the mushrooms, half the pearl onions, 1/4 tsp salt, 1/8 tsp pepper and cover.

Cook 8-10 minutes until mushrooms have released their moisture. Uncover and cook an additional 12-15 minutes until pan is dry.

Remove these vegetables from the pan, set aside, and repeat with the other half. 

Add remaining 2 Tbsp oil and flour to the now empty pot and whisk until no dry flour remains. Whisk in broth, 2 cups wine, agar, tomato paste, and miso paste until no lumps remain, making sure to scrape up any browned bits from the bottom of the pot. 

 Stir in chopped onions, carrots, garlic, porcini mushrooms, parsley sprigs, bay leaves, peppercorns. Bring to a boil and cook until the liquid is slightly thickened and onions are translucent and softened, about 15 minutes.

Strain this liquid through a fine mesh strainer and discard the solids. Return the liquid to the pot and stir in remaining wine. Bring mixture to a boil over medium high heat and cook until thickened to the consistency of heavy cream, approximately 5-7 minutes. 

Reduce heat, and stir in reserved mushroom and onion mix from before. Cook until heated through.

Stir in minced parsley, and salt and pepper to taste. Serve over mashed potatoes, rice, or cauliflower puree.