Whisk eggs together in a large bowl until light and frothy; stir in milk. Stir in cornmeal and salt. Add oil; stir until batter is smooth.
Place shortening in a 10-inch cast iron skillet; heat skillet in the preheated oven until shortening is liquefied, 2 to 3 minutes. Remove skillet and pour in batter.
Return skillet to oven and bake until corn bread is lightly browned, 25 to 30 minutes.
Remove skillet from oven immediately and cover with wooden cutting board. Use oven mitts to invert skillet and tip corn bread onto cutting board. Cut into 8 wedges.
