Canola oil, for frying
1 large russet potato, peeled
Kosher salt, to taste
2/3 lb. ground beef
1/4 lb. fresh chorizo, casings removed
1/4 cup finely crushed saltine crackers (about 6)
1 tbsp. finely chopped yellow onion
1/2 tsp. smoked Spanish paprika
1 clove garlic, finely chopped
Freshly ground black pepper, to taste
6 soft hamburger buns, toasted
Ketchup, for serving
1. Heat oven to 200°. Pour oil into a 4-qt. saucepan until it reaches a depth of 2"; heat over medium-high heat until a deep-fry thermometer registers 330°. Meanwhile, working over a large bowl, grate potato using the large-holed side of a box grater. Soak grated potatoes in water for 1 minute and drain. Spread potatoes on a kitchen towel and pat dry. Working in batches, fry potatoes until golden brown, about 2 minutes. Using a slotted spoon, transfer potatoes to paper towels and season lightly with salt; set aside.
2. In the bowl of a food processor, combine the ground beef, chorizo, crushed crackers, onions, paprika, garlic, salt, and pepper; process until mixture forms a ball around the blade. Transfer meat mixture to a bowl and cover with plastic wrap; refrigerate for 30 minutes.
3. Form meat into 6 thin patties. Heat a 12" cast-iron skillet over medium heat; add the patties and cook, flipping once, until browned and cooked through, 5–6 minutes. Transfer burger patties to a plate. Spread some ketchup on the bottom half of each bun and top with a burger patty and a mound of the fried potatoes.
MAKES 6 BURGERS