Bring a large pot of salted water to a boil, then add the pasta and cook until just al dente, about 8-10 minutes. Drain, reserving half a cup of the pasta water.
While the pasta cooks, slice the cremini mushrooms into thick slices and finely mince the garlic cloves.
Heat a large skillet over medium heat and add the olive oil. Once shimmering, add the sliced mushrooms and cook, stirring occasionally, until deeply browned and fragrant, about 8 minutes. They should develop a rich, caramelized color.
Push the mushrooms to one side of the skillet and add the minced garlic to the cleared space. Sauté for about 30 seconds until fragrant, being careful not to burn it.
Mix the garlic into the mushrooms, then pour in the reserved pasta water and lemon juice. Let simmer for 2 minutes, allowing the mixture to slightly thicken and develop a glossy, flavorful sauce.
Add the drained pasta directly into the skillet. Toss everything together, ensuring each strand is coated with the mushroom sauce. If it feels too thick, add a splash more of the reserved pasta water.
Sprinkle the nutritional yeast over the pasta and toss again, allowing it to melt into the sauce for a cheesy, umami flavor. Adjust seasoning with salt, pepper, or more lemon if desired.
Remove from heat and transfer the pasta to serving bowls. Garnish with chopped fresh herbs for a burst of color and freshness.
Finish with an extra squeeze of lemon for brightness and serve immediately while hot and silky.
