Slice off the top third of each white onion and cut an “X” at the base. Place the onions in a steamer and cook for 10 to 15 minutes, or until tender. Reserve.

Meanwhile, cut an “X” on the bottom of each pearl onion and poach in boiling, salted water for 5 minutes. Drain and peel.

Blanch the peas in salted boiling water for 4 minutes. Drain and mix with the pearl onions.

Peel off the outer skin and scoop out the heart of the larger onions to make onion shells.

Coat the pearl onions and peas with vinaigrette and spoon into the hollowed onions. Serve at room temperature.