Bring a pot of water to a boil. Add pearl onions and cook for 3 minutes. Drain and rinse under cold water. Peel onions and remove the ends.

Place onions back into the pot. Add peas and fill with just enough water to cover. Simmer until tender, about 10 to 12 minutes. Drain and transfer to a bowl.

Melt margarine in the same pot over medium-high heat. Add cream, salt, pepper, onion powder, and garlic powder; bring to a boil. Cook, stirring constantly, until sauce thickens, about 5 minutes. Add peas and onions and stir until coated.

Serve immediately.