Place the frozen peas in a small bowl and set aside.
In a large skillet over medium heat, cook the chopped bacon until it’s crispy and golden, about 6–8 minutes. Use a slotted spoon to transfer the bacon to a paper towel-lined plate, leaving about 1 tablespoon of bacon grease in the skillet.
Add the diced onion to the skillet and cook in the bacon grease for 3–4 minutes, until soft and translucent. Remove from heat and set aside.
Bring a large pot of water to a boil. Add the ramen noodles and cook just until tender, about 2–3 minutes. Reserve 1 cup of the pasta water, then drain and set noodles aside.
While the noodles are cooking, whisk together the eggs, grated Parmesan cheese, salt, and a generous pinch of black pepper in a small bowl. Slowly whisk in 1/4 cup of the reserved hot pasta water to temper the eggs—this helps prevent scrambling.
Immediately return the drained noodles to the warm skillet (off the heat) with the onions. Quickly pour in the egg mixture and toss well to coat the noodles, letting the residual heat cook the sauce until it’s creamy and clings to the noodles. If you need to loosen the sauce, you can add a little of the remaining reserved pasta water at a time, tossing the pasta until it is the consistency you are looking for.
Add the bacon and thawed peas and gently toss them with the creamy pasta.
Divide the ramen carbonara between bowls and top with extra Parmesan and black pepper, if desired.