Bring a large pot of salted water to a boil, add pasta and cook according to package directions.

Drain pasta, reserving 1 cup of pasta water and return pasta to the pot

Meanwhile, heat oil in a medium skillet over medium heat.

Add onion and garlic, cook until onion is translucent, about 3 min.

Add butter, ham and peas; cook, stirring occasionally until heated through, about 3 min more.

Reduce heat to very low.

Add sauce, salt and pepper to the pasta.

Toss adding enough pasta water to make a light sauce.