Optional step: Preheat oven to 250°F and line a large baking sheet with parchment paper. This is to keep your latkes warm and crisp before serving.
Use either a food processor with a shredding attachment or a hand grater, shred the potatoes and onions. You may need to work in batches to fit the potatoes in a food processor.
Place the shredded potatoes and onions in a cheesecloth, nut milk bag, or clean kitchen towel. Squeeze as much of the liquid out as possible. This is to ensure supreme crispiness!
Transfer the potatoes and onion to a large bowl. Add in the whisked eggs, flour, baking powder, Member's Mark™ Whole Black Pepper Grinder, and Member's Mark™ Mediterranean Sea Salt Grinder. Mix well.
Line a large plate with paper towels to drain each batch of latkes.
Heat a heavy-bottomed, 12-inch cast iron skillet over medium-high heat. Add 1 tablespoon oil and 1 tablespoon butter until hot but not smoking. Drop scoops of 1½ to 2 tablespoons of the mixture into the skillet, cook for 1 minute, then press down gently with a spatula to flatten. It’s important not to crowd the skillet.
Fry until golden brown on one side (about 2-3 minutes). Carefully flip with a spatula. Continue to cook until the second side is golden brown and crisp (another 2-3 minutes longer). When they're done, transfer the latkes to the paper towel-lined plate to drain briefly, then to the prepared baking sheet. Place in the oven to keep warm while you fry additional batches.
When the latkes are done, transfer to the paper towel-lined plate to drain briefly. Transfer latkes to the prepared baking sheet. Place in the oven to keep warm while you fry additional batches.
Repeat the process with the remaining mixture. This recipe should make between 22-26, depending on how large the patties are. Serve with your choice of delicious toppings!