Directions

1. Heat 1 tablespoon olive oil in a medium saucepan over medium heat. Add onion and thyme. Cover and cook, stirring often for 15 minutes or until soft and lightly golden. Uncover and cook for a further 3 minutes. Remove thyme sprig and set aside.

2. In last 3 minutes of onion cooking, heat a large frying pan over medium-high heat. Rub steaks with extra oil and season with salt and pepper. Cook for 2 minutes each side, or until cooked to your liking. Remove from heat and allow to rest for 2 minutes. Cut into thick slices.

3. Meanwhile, toast 1 slice of bread. Combine mayonnaise and Dijon mustard. Spread toasted bread with half of the mayonnaise mixture. Top with half the caramelised onion, 1/2 cup rocket, 1 steak, half of the beetroot, and half of the Sauerkraut.

4. Pack remaining ingredients away to construct sandwich for lunch tomorrow.