Preheat oven to 350 degrees F.
In a large oven-safe skillet, melt butter and olive oil. Add the turnip, carrot, parsnip and celery. Cook until they start to soften, about 2 minutes. Add a teaspoon of salt.
Add shallot and cremini mushrooms. Cook for 2 minutes. (Hold the portobellos until the end.)
Sprinkle in cinnamon and French spice blend. Stir to coat all of the vegetables.
Add the Burgundy wine and cook for a couple of minutes to give the alcohol a chance to burn off.
Stir in flour to thicken the sauce a bit. Cook for 2 minutes.
Stir in tomato paste. Add the bouquet garni and 2 cups of vegetable broth. Cover the skillet and put in the oven for a half hour.
In a separate frying pan add the portobello mushrooms and pearl onions with a little olive oil and heat up to start to caramelize. Just a few minutes. You don’t need to cook them all the way through.
Remove the skillet from the oven, remove the bouquet garni. Add the portobellos and pearl onions. Put the lid back on and return to the oven for 15 minutes.
Remove from the oven. Check to make sure there is enough liquid. Make sure everything is soft. Return to the oven without the lid so it can thicken up and become stew-like. This will take about 15 minutes.
Serve with mashed potatoes. Garnish with freshly chopped parsley.