How to Make It
Heat olive oil in a large skillet over medium. Add shallots, broccoli, and zucchini, and cook, stirring often, until slightly browned, about 3 minutes. Add ham, and cook 2 minutes. Remove from heat, and let cool.
Coat bottom and 2 inches up sides of a 5-quart slow cooker with cooking spray; add vegetable mixture.
Whisk together eggs, Parmesan, basil, salt, and pepper; pour over vegetables in cooker. Cover slow cooker, and cook on high until frittata is set and the tip of a knife inserted into center comes out clean, about 1 hour and 45 minutes. Cut into 8 slices; lift slices out with a spatula to plate.