Bring a large pot of salted water to a boil and cook the pasta according to package directions until al dente. Drain, reserving 1 cup of pasta water.

While the pasta cooks, heat 2 tablespoons butter in a large skillet over medium-high heat. Add the mushrooms in a single layer and let them sit undisturbed for 3-4 minutes until golden. Stir and cook another 3-4 minutes until they release their liquid and begin to brown. Season with salt and pepper, then transfer to a plate.

Reduce heat to medium. Add the remaining 4 tablespoons butter to the same skillet and let it melt and foam. Watch carefully for 2-3 minutes, swirling occasionally, until it turns golden brown with a nutty aroma.

Add the sage leaves and minced garlic to the brown butter and cook for 30 seconds until fragrant.

Pour in the white wine and scrape up any browned bits from the pan. Simmer for 1 minute to reduce slightly.

Add the cooked pasta and mushrooms to the pan along with 1/2 cup pasta water. Toss gently over low heat for 1-2 minutes, adding more pasta water if needed to create a silky sauce. Remove from heat.

Grate the parmesan over the pasta and toss once more. Taste and adjust seasoning with salt and pepper. Finish with a squeeze of fresh lemon juice.