Covering the onion and zucchini for a few minutes while they cook helps them steam evenly; once the pan is uncovered, let the liquid evaporate so the frittata will be firm.
Everyday Food, May 2004
Prep Time 35 minutes Total Time 1 hour 10 minutes Yield Serves 8
tags: vegetarian, brunch, CSA
source: http://www.marthastewart.com/333240/zucchini-tomato-frittata