Combine the shallots with buttermilk, salt, and pepper, then set aside.
In a medium bowl, whisk together the flour, corn starch, salt, and pepper.
Fill a medium pot with oil about 1 inch up the sides, then place over medium-high heat.
Drain the shallots well, then working in batches, add them to the flour mixture and toss them around so that every piece is separated and coated with flour. Remove them from the flour, place them into a strainer and shake off as much excess flour as possible.
Test the oil by sprinkling a little bit of flour in it. The flour should immediately sizzle and start to brown, but not burn. If using a thermometer, it should read between 350-375 degrees.
Carefully drop the shallots into the hot oil. Move them around for a few minutes, flipping if necessary, until golden brown.
Remove fried shallots with a spider or slotted spoon, then place them on paper towels to drain.