Preheat a deep-fryer filled with oil to about 3/4 of the way full to a temperature of 375 degrees F. While the oil is heating, combine the cornmeal, flour, sugar, salt, Memphis Rib Rub, baking powder, baking soda and black pepper in a mixing bowl and whisk to combine. In a second mixing bowl, whisk together the eggs, buttermilk, grated onion, green onions and jalapenos. Add the wet ingredients to the dry ingredients and stir just until a batter comes together. Be careful not to overmix. When the oil is hot, drop 1 1/2 tablespoons of the batter at a time into the hot oil and fry, turning occasionally, until golden brown on all sides and cooked through, 3 to 4 minutes. Remove using a slotted spoon and let rest on a paper lined plate briefly before serving hot.