Place the stock in a small pot and heat over medium low. You want the stock to be warm when adding it to the risotto so that the temperature change does not affect the rice.
Clean, trim, and cut your mushrooms into pieces, as large or small as you prefer.
In a large pot, melt 3 Tablespoons of the butter over medium heat. When melted, add your mushrooms.
Cook the mushrooms until they are just starting to release their liquids, or as soft/firm as desired. Remove the mushrooms from the pot, leaving any remaining butter, and set aside.
Add 2 Tablespoons butter to the pot. Add the red onion to the pot when the butter has melted. Cook until the onion is translucent but not yet browning, approximately 3-5 minutes.`
Add the rice and stir. Continue cooking to slightly toast the rice until it is just starting to show a little brown color, approximately 3-5 minutes.`
Add the white wine to the pot. Cook until the rice is almost dry, where most of the wine has been absorbed.
Add the thyme and one cup of stock to the rice. Stir continuously until most of the stock has been absorbed. Repeat this process 1/2 cup of stock at a time until the rice is cooked thoroughly. You want the rice to have just a little bit of bite left so that it is not completely mushy. Depending on your rice, you may need more or less stock for the right consistency so start tasting the rice after 4 cups.
When your rice is cooked through, remove the pot from the heat. Add the remaining butter and Parmesan cheese. It is important to do this before adding salt and pepper because the cheese is salty. Stir to combine and until the cheese and butter have melted into the risotto.
Stir in your mushrooms. Taste the risotto and season with additional Parmesan, salt, and pepper as desired. Depending on your cheese, you may need no salt, or a couple teaspoons. Serve immediately.
Notes
Get arborio rice online here.Use any white wine that you enjoy drinking. I advise staying away from sweet wines as it will make the risotto very sweet as well. Chardonnay or sauvignon blanc are the ones I tend to use.To ensure a truly vegetarian dish, use vegetarian cheeses.Use any mixture of mushrooms that you like, or even just one variety. Cut them as large or small as you want.