In a large mixing bowl, whisk together the flour, sugar, cornmeal, baking powder, and salt until well combined.

Gradually pour in the milk into the dry ingredients while stirring continuously until the batter is smooth.

Fold in the finely chopped onions until evenly distributed in the batter.

In a skillet, pour in about 1/2 inch of oil and heat it until shimmering, around 350°F (175°C).

Spoon approximately 2 tablespoons of the batter into the hot oil for each fritter, flattening them lightly. Fry for 2-3 minutes on each side until golden brown.

Remove the fritters and place them on paper towels to drain excess oil, allowing them to cool slightly before serving.