Note: I make the mushrooms and risotto in two skillets at the same time, but wrote the directions separately for clarity. These are great together or separately as side dishes.
Make the mushrooms: Combine the vegetable stock with the dried mushrooms in a small pot. Cover the pot and bring to a boil on the stove. Boil the mushrooms for 5 minutes, then turn the heat off and let the mushrooms steep covered for 15 minutes. Remove the mushrooms from the stock with a slotted spoon to cool. Chop any large mushrooms into bite-sized pieces, and reserve the stock.
In a skillet, melt 1 tablespoon of the butter over medium-high heat. Add the fresh mushrooms and stir for 5 minutes to soften the mushrooms slightly, then add the onion. Cook the onion for 3 minutes with the mushrooms, then stir in the tomato paste.
Add about a cup of the mushroom cooking stock to the skillet and reduce the heat to medium. Simmer the mushrooms until they are very dark and tender, adding more stock as you to to maintain a sauce. You will use at least 2 cups of the veggie/mushroom stock, maybe 3.
After about 15 minutes, add the reconstituted dried mushrooms to the skillet with some more stock. Taste the mixture and add salt and pepper to your preference. Continue to cook until the sauce has reduced and coats the mushrooms, then stir in the remaining tablespoon of butter and serve as desired.
Make the risotto: In a skillet over medium-high heat, melt the butter. Add the onion and saute for two minutes to soften, then add the rice and garlic to the skillet. Stir for two minutes more to coat the rice in the butter and soften the garlic.
Add the wine to the skillet and stir until the wine is reduced. Repeat with the stock; add half a cup of stock at a time and stir until the liquid is absorbed, then add more to the skillet. After about 25 minutes, the rice should be cooked. You may not use all of the stock. When the rice is tender, add salt and pepper to your taste and stir in the mascarpone cheese.
Serve the risotto topped with some mushrooms and a pile of microgreens for freshness and flavor.
Use any kind of mushrooms you like or can find! I found a wild mushroom blend at Whole Foods and used a fresh blend from my regular grocery store. Even just fresh cremini mushrooms and dried porcini would be wonderful.