Wash and dry all produce. Bring a large pot of salted water to a boil. Trim, then thinly slice mushrooms. Cut green beans into 2-inch pieces. Roughly chop sun-dried tomatoes. Cut lemon into wedges.

Heat a drizzle of olive oil in large pan over medium-high heat. Add mushrooms to pan and cook, tossing, until tender, 4-5 minutes. Season with salt and pepper. Remove from pan and set aside.

Once water is boiling, add green beans to pot. Cook until just barely tender, 2-3 minutes. Remove from pot with a slotted spoon, place in a strainer, and rinse under very cold water (keep the pot of boiling water on stove for the gnocchi). Remove beans from strainer and set aside.

Add gnocchi to same pot of boiling water. Cook, stirring occasionally, until just softened, 2-3 minutes, then drain, tossing gently in strainer to remove excess moisture.

Melt 1 TBSP butter in pan used for mushrooms over medium-high heat. Add gnocchi to pan and cook, tossing, until lightly browned, 3-5 minutes.

Add pesto, sun-dried tomatoes, green beans, half the Parmesan, and mushrooms to pan with gnocchi. Cook, tossing, until combined and warmed through, 1-2 minutes. Season with salt and pepper. Divide between bowls, then sprinkle with remaining Parmesan. Serve with lemon wedges for squeezing over.