Defrost peas by placing in a colander and running warm water over them until they are completely defrosted and tender, then set aside to allow them to drain.
Place a large skillet over medium heat and add olive oil. Add onion and cook until tender and translucent, about 3–4 minutes. Add garlic and cook 1 additional minute.
Add defrosted peas and any water that is still clinging to them. Season lightly with salt and pepper, keeping in mind that the cheese will have a fair amount of salt as well.
Continue cooking just until the peas are hot, about 3–4 minutes. Sprinkle with grated Parmesan or Romano cheese, stir to combine, then transfer to a serving dish and enjoy.
Notes
Serve as a side or toss with your favorite pasta dish!