In a medium saucepan, bring the entire can of Dei Fratelli Tomato Juice to a soft boil.
Add 1 Tbsp. of extra virgin olive oil to a separate, large skillet over medium-high heat. Add all of the sliced mushrooms and cook until softened; about 4 minutes. Remove the mushrooms from the skillet and set off to the side.
Add another tablespoon of olive oil to the large skillet used for the mushrooms. Put in diced shallots and cook over medium-high heat for 1 minute.
Once the shallots have softened, add in the arborio rice. Stir the rice for 2 minutes, coating it in the oil.
Once the rice has a pale, golden color, add in the white cooking wine and stir well.
Add 1 cup of Dei Fratelli Tomato Juice that has been warming in your medium saucepan to the rice mixture. Stir frequently until the rice absorbs all of the tomato juice.
Add another cup of warmed tomato juice and stir again until the juice is well absorbed.
Repeat this process until you have about 1 cup of tomato juice remainning
Add in the last cup of warmed juice along with the spinach. Mix until the tomato juice is absorbed and your rice is at your desired consistency.
Remove both pans from heat, and stir cooked mushrooms, butter, and mascarpone into your homemade risotto.
Garnish your risotto with shredded parmesan cheese, fresh chives, and thyme.