Place enough peanut oil in a 4 to 5-quart cast iron Dutch oven to come halfway up the side of the pot. Place over medium-high heat and bring to 390 to 400 degrees F.
Remove the pickles from their brine and cut lengthwise into quarters, like spears. Lay the spears on a sheet pan lined with paper towels and pat them dry.
Place the buttermilk in 1 shallow dish and mix together the cornmeal and salt in a separate dish. Dip each pickle, 1 at a time, first into the buttermilk, then into the cornmeal and then repeat. Carefully place each spear into the hot oil and cook until golden brown, approximately 2 minutes. You can fry 3 to 4 pickles in the pot at a time. Adjust the heat, if necessary, in order to maintain a constant temperature of 390 to 400 degrees F. Transfer the pickles to a cooling rack set in a half sheet pan and allow to cool for 5 minutes before eating. Season with additional salt, if desired.