This flavorful frittata can be a simple brunch or weeknight supper dish; if you don't have fresh thyme, just substitute dried. The recipe comes from Urban Roots Farm in Springfield, Missouri.
In a medium mixing bowl, beat together the eggs, milk, thyme, 1/4 teaspoon of the salt and the pepper. Set egg mixture aside.
Scrub potatoes and peel, if you like. Rinse and dry well. Slice potatoes in half lengthwise. Cut each of the halves crosswise into thin, half-circle slices (measure 2 cups). Set potatoes aside.
In a 9- or 10-inch cast-iron skillet or a large ovenproof skillet, melt butter over medium heat. Add onion, garlic and the remaining 1/4 teaspoon of the salt. Cook, uncovered, for 2 minutes, stirring occasionally. Add potatoes. Cook for 7 to 10 minutes or until potatoes are just tender and starting to brown, stirring occasionally. Spread vegetable mixture evenly across the bottom of skillet.
Pour egg mixture over vegetable mixture in skillet. Cook over medium heat. As mixture sets, run a spatula around edge of skillet, lifting egg mixture so uncooked portion flows underneath. Continue cooking and lifting edges until egg mixture is almost set, about 6 to 8 minutes total (surface will be moist).
Place skillet in a 350° oven and bake, uncovered, for 6 to 8 minutes or until top is just set. (Or place skillet under a preheated broiler, 4 to 5 inches from heat. Broil for 1 to 2 minutes or until top is just set.)
Let stand 10 minutes before serving.