Cut into squares, a 9x13 pan should feed 8 to 10 people. It does take longer to cook, since you aren't starting it on the stovetop before moving it to the oven.
Here's what to do:
• Sauté vegetables in a large skillet (we used a mixture of onion, slivered asparagus, and mushrooms) just until soft, not fully cooked through.
• Beat a dozen eggs with a generous pour of milk, plus some salt and pepper.
• Spread the cooked vegetables in the bottom of a greased 9x13 baking pan. (We lined ours with parchment paper to make sure the egg wouldn't stick.) Pour over the eggs.
• Dot the entire pan with generous lumps of cheese. Ours was goat cheese.
• Bake at 375 degrees for about 45 minutes, until the top is just set.
• Let cool for a few minutes, then cut into squares and serve.
Next time you have a few more people than a skillet frittata will feed, consider making these squares. We also found that they're great left over.Related: Tip: Put Leftover Pasta in Your Frittata
(Images: Elizabeth Passarella)