Add the remaining butter to the skillet over medium-low heat. Stir in the mushrooms and garlic, cooking until the mushrooms soften, about 6 to 8 minutes. Add in the pasta, swiss chard, stock, salt and pepper. Bring the mixture to a boil and then cook for 8 to 10 minutes, stirring, so the pasta cooks. Once the noodles have absorbed all of the water, remove the pot from the heat. Stir in the reserved brown butter. Stir in the parmesan cheese and serve, adding more on top if desired.