Smothered Potato Latkes

Heat 1 tablespoon olive oil in a large skillet over medium-low heat. Add sliced onion and cook, stirring occasionally, until starting to brown, 6 to 8 minutes. Stir in water, scraping up any browned bits. Continue to cook, stirring occasionally, until the onion is brown and soft, about 1 minute. Transfer to a plate.

Add the remaining 1 tablespoon olive oil and mushrooms to the pan. Cook, stirring occasionally, until browned, about 8 minutes. Season with 1/2 teaspoon each salt and pepper. Return the onion to the pan, add brisket and mix well. Cover and set aside.

Preheat oven to 300°F. Set a wire rack on a baking sheet and place it in the oven.

Using a food processor fitted with the shredding disk, shred potatoes and quartered onion, alternating them. Transfer to a bowl and let stand for 5 minutes.

Using a slotted spoon, transfer the shredded vegetables to a clean kitchen towel set over a large colander. Set the colander in a large bowl and twist the towel to squeeze the moisture out. Carefully pour off the liquid from the bowl, taking care to leave behind the white, starchy paste at the bottom. Add the squeezed vegetables to the bowl with the starch.

Add egg yolks, matzo meal and the remaining 1 teaspoon salt and 1/4 teaspoon pepper to the potato mixture. Mix thoroughly to combine. Beat egg whites in a medium bowl with an electric mixer until they are shiny and form stiff peaks. Fold the whites into the potato mixture.

Heat canola (or grapeseed) oil in a large skillet over medium heat until it reaches 375°F. Working in batches, drop several golf-ball-size spoonfuls of the potato mixture into the hot oil. Using a spatula, press down to make latkes about 1 1/2 inches wide. Cook, flipping once, until browned, 5 to 7 minutes total. Transfer to the rack in the oven while you fry the remaining latkes, making sure the oil returns to 375°F before cooking each batch.

Reheat the reserved brisket mixture, if necessary. Serve the latkes topped with the brisket mixture. Garnish with chives, if desired.