Beat together eggs, water, cheese, salt and basil. Stir in piperade. Heat oil in 10to 30 cm nonstick skillet. Add ham; saute over medium-high heat for 2 minutes. Cook until set on bottom. Reduce heat to medium. With spatula, lift edges of fri ttata so uncooked egg runs underneath. Cook until set, 1 to 2 minutes. Continue lifting and cooking until egg is completely set and lightly browned on underside. Flip frittata and brown top side, about 2 minutes. Transfer to platter; dust with pepper. Cut into 4 wedges. Top with tomato sauce, if desired.