Bring a large pot of salted water to a boil. Cook pasta until al dente. Reserve ½ cup of pasta water before draining.
In a bowl, combine ricotta, olive oil, Parmesan, lemon zest, lemon juice, garlic, salt, and pepper. Stir until smooth.
In the last minute of pasta cooking, add spinach to boiling water. Drain spinach and pasta together.
Return drained pasta and spinach to the pot. Add ricotta mixture and a splash of reserved pasta water. Stir gently to combine.
Adjust seasoning. Add more pasta water if needed to reach a creamy consistency. Finish with pepper and a squeeze of lemon.
Plate the pasta warm. Drizzle with olive oil and sprinkle extra Parmesan. Serve with lemon wedges if desired.
