Prepare the Grits:
In a large saucepan, bring the 2 cups of milk, 2 cups of water, and 1/4 tsp salt to a simmer over medium-high heat.
Reduce the heat and stir in the instant grits. Cover the pan and cook for about 5 minutes, or until the grits thicken.
Remove from heat and stir in the shredded sharp cheddar cheese and black pepper until well combined.
Chill the Grits:
Spread the cooked grits mixture into a baking dish and chill for at least 3 hours, or until fully set.
Coat the Grit Cakes:
Once the grits are chilled and firm, use a round cookie cutter to cut out individual cakes.
In one shallow dish, whisk together the 3 eggs and 2 tbsp milk. In another dish, combine the Panko breadcrumbs and Creole seasoning.
Dip each grit cake into the egg mixture, then into the breadcrumb mixture. Repeat the dipping process to ensure a double coating.
Fry the Grit Cakes:
Heat enough oil in a large skillet over medium heat to cover about 1/2 inch of the pan.
Fry the grit cakes for 2-3 minutes on each side, or until golden brown and crispy.
Transfer the fried cakes to a paper towel-lined plate to cool slightly before serving.