Begin by finely chopping cremini mushroom, shallot, and garlic. Pick the fresh thyme and give it a rough chop.
In a small pot warm up your vegetable stock to just under a simmer and reserve.
Pre heat a sauté pan over medium heat and add the olive oil. When it shimmers and you see small wisps of smoke add the mushrooms. Sauté until the mushrooms have released all of their water and begin to turn golden brown, around 5 minutes.
Add the butter, once it melts and begins to foam add the shallot, garlic, and thyme and a pinch of salt. Sauté until the shallots are slightly translucent, around 2 minutes. Add the orzo and briefly toast for 1 minute. Deglaze with the white wine and cook until wine is almost gone.
Add your warm vegetable stock and bring to a simmer. Cook until the liquid is nearly gone and the orzo is fully cooked around 8 minutes.
Add the mascarpone and mix to combine. Taste and adjust your salt and pepper, if you would like to adjust the consistency you can add a splash of vegetable stock.
Add to a bowl and top with parmesan, serve immediately.