Step 1
Make the filling: Strip leaves away from chard, and dice the stems into 1/2-inch pieces. Set a large frying pan over medium-high heat. Add 3 tablespoons olive oil. When oil shimmers, add the onion, diced chard stems, and a pinch of salt. Reduce heat to medium and cook, stirring occasionally, for 12 to 14 minutes, until onions are tender and lightly golden.