Add frozen peas to a microwave-safe bowl. Microwave for 2-3 minutes or until they are warm.
Once the pasta is al dente, carefully scoop out ½ cup of pasta water. Drain the pasta and return it to the pot.
Add ¼ cup of pasta water, Pecorino Romano, butter, and pepper. Mix until a creamy sauce is formed. Then mix in the peas, mint, and lemon juice. If the pasta is dry, add more pasta water 1 tablespoon at a time.