Preheat oven to 350°F. Using kitchen shears, cut bacon into 1-in. pieces directly over a 10-in. oven-safe skillet. Place over medium-high heat and cook, stirring occasionally, until bacon is crisp, about 5 minutes. Stir in corn and green onions. (To make it meatless, skip the bacon. Instead, add 2 Tbs. olive oil to the pan, and cook 4 oz. sliced shiitake mushrooms until crisp and golden, about 5 minutes. Sprinkle with a pinch of salt.)
Whisk together eggs, milk, salt, and pepper in a medium bowl. Pour the egg mixture over the bacon-corn mixture and cook over medium heat for 3 minutes.
Transfer to the oven and bake until just set, 12 to 14 minutes. Let stand for at least 5 minutes before slicing and serving.
Bust out a cookie cutter and stamp cool shapes from the frittata.