Rachael's Burger of the Month: Okto-Burgers – Rachael Ray

Ingredients

• 1 ½ lb. 80% lean ground beef
• Kosher salt and coarse black pepper
• ¼ cup Worcestershire sauce
• 1 tsp. ground white pepper
• About 1/4 tsp. freshly grated nutmeg
• 1 small to medium white onion, very thinly sliced with a sharp knife or a mandoline
• ½ cup distilled white vinegar
• 2 tsp. sugar
• 1 tbsp. olive or canola oil
• 8 slices Swiss cheese
• 1 jar or pouch (16 oz.) sauerkraut
• 1 tsp. each caraway seeds and cumin seeds
• 4 pretzel rolls, split
• Brown mustard, for spreading
• Dill pickle chips, for topping