Into a large bowl, sift together the flour, salt, baking powder and sugar. Add the buttermilk, oil and egg and stir just until blended, being careful not to over mix. (Lumps are okay.) Let the batter stand, refrigerated, at least 1 hour, and up to 8 hours.
Preheat a large, heavy skillet or griddle over medium-high heat. Lightly grease with enough vegetable oil to leave a film on the bottom. Working in batches, ladle batter by 2/3 cupfuls onto the pan. Cook, turning once, until the pancakes are golden brown, about 2 to 3 minutes per side. Transfer to plates and serve warm with unsalted butter and syrup.
Makes about 12 to 15 medium cakes