Remove the sourdough discard from your starter. Go ahead and feed your sourdough starter after removing the discard.Add the discard, flour, kefir (or buttermilk) and sugar to a large mixing bowl. Whisk until incorporated and fairly smooth.

Cover the bowl with a lid or a towel.Short Ferment: Let the batter rest for at least 2 hours at room temperature (70°F -75°F). You'll begin to see bubbles rising up in the batter.Longer Ferment (for Stronger Sourdough Flavor): Let the batter rest for 12 hours or overnight at room temperature (70°F -75°F). The batter will rise somewhat as it rests and become very bubbly. After a long ferment, gently deflate the dough with a spoon or whisk.

Whisk the eggs and melted butter in a small bowl. Make sure the butter has cooled slightly so that the eggs don't scramble.The batter will be somewhat thicker than a traditional pancake batter, but should still be easy to stir. If your batter seems too thick, add a little extra kefir or buttermilk to the batter.Gently whisk the egg and butter mixture into the batter.Add the salt and baking soda to the batter and gently whisk again until just incorporated. (Avoid over-mixing.) At this point, the batter will begin to bubble and rise.

Preheat a griddle over medium heat. Spray with oil (or brush with butter) if not non-stick.Use a ⅓ cup measuring cup to pour batter onto the hot griddle, using the back of the cup to help shape the pancake into a circle if desired.Note that this is a very thick batter and likely will not spread out much on the griddle.

As the pancake cooks, the edges will begin to pull away from the griddle. Use a large, flexible spatula to test the bottom of the pancake and check to see if it's golden. You can also look for bubbles setting in the pancake to know when to flip, but because this batter is so thick, the bubbles are a less reliable method.When the bottom of the pancake is golden, flip it. Cook until both sides are golden.Repeat with remaining batter.

Keep pancakes warm in a 190°F oven while you finish cooking the batter, or until ready to serve. Serve warm with berries or nuts (if using), butter, and maple syrup or honey.Leftover pancakes (Fridge): Wrap pancakes in foil and store for up to one day in the fridge. Reheat in a toaster, toaster oven or microwave until warm (about 30 seconds). Leftover pancakes (Freezer): To freeze, wrap the pancakes in wax paper and store in an air-tight container for up to 2 months. Reheat in a 350°F oven for 8-10 minutes, on a griddle until warm, or in the microwave for 1-2 minutes.