Mix the Dry Ingredients: In a medium-sized mixing bowl, whisk together the all-purpose flour, granulated sugar, cornmeal, and baking powder. Ensure the baking powder is evenly distributed throughout the flour.

Create the Batter: Gradually pour the whole milk into the dry ingredients, stirring continuously. Mix until the batter is just smooth and no dry pockets of flour remain. Be careful not to overmix, which can develop the gluten and make the fritters tough.

Fold in the Onions: Gently fold the chopped white onions into the batter until they are evenly coated. Season the mixture generously with kosher salt and freshly ground black pepper to taste.

Heat the Oil: In a heavy-bottomed skillet (such as cast iron), pour in about 1/2-inch of your chosen cooking oil. Heat over medium-high heat until a frying thermometer registers exactly 375°F. (Tip: If you don't have a thermometer, drop a tiny, pea-sized amount of batter into the oil; if it sizzles vigorously and floats to the top immediately, the oil is ready).

Fry the Fritters: Carefully drop tablespoon-sized portions of the onion batter into the hot oil. Use the back of your spoon or a spatula to gently press each fritter down slightly, flattening them into discs so they cook evenly to the center.

Achieve Golden Perfection: Fry the fritters for about 2 to 3 minutes per side. Watch them closely; you are looking for a deep, golden-brown crust and crispy edges.

Drain and Serve: Remove the cooked fritters from the oil using a slotted spoon. Let them drain immediately on a plate lined with paper towels, or on a wire cooling rack, to absorb any excess oil. Serve immediately while hot and crispy for the best texture!