Add enough oil to a thick stock pot or Dutch oven to fill to 2-3 inches high. Heat to 350 F.
In a mixing bowl, combine corn meal, flour, salt, and baking soda, stirring to evenly distribute. Stir in the mixed onion.
In a separate bowl, lightly whisk eggs and buttermilk together.
Drop the wet mix into the dry mix, and stir until just combined. Over-mixing will make the puppies tougher.
Drop heaping teaspoon-sized balls of batter into the oil, frying until golden brown. They should flip over on their own when the bottom is cooked, but if they don't, a light nudge should do the trick. Remove with a slotted spoon to a paper towel lined plate to drain. To avoid crowding, it may be best to do this step in smaller batches.
Notes
Like 'em sweet? Add 1/4 cup sugar to the dry ingredients.