Swiss Chard Frittata - Whole Living

Ingredients

• 1 large egg
• 10 large egg whites
• 1/3 cup fresh part-skim ricotta cheese, pressed through a fine sieve
• 1/2 teaspoon coarse salt
• 1/8 teaspoon freshly ground pepper
• 1 teaspoon extra-virgin olive oil
• 2 leaves Swiss chard (4 ounces), sliced 1/2 inch thick crosswise (1 1/4 cups), stalks removed and chopped into 1/2-inch pieces (1/2 cup)
• 1/2 large onion (4 ounces), thinly sliced crosswise (1/2 cup)