- 90ml brown lentils, rinsed, strained and picked through
- 250ml low-sodium vegetable broth or water
- 1 tsp extra-virgin olive oil
- ½ large red onion, half finely chopped and half thinly sliced
- Juice of 1/4 lemon
- 100g fresh baby spinach
- 1 large cloves garlic, minced
- Freshly ground black pepper
- ½ tsp ground cumin
- 60 ml (1/4 cup) walnuts, toasted and finely chopped
- Bring the lentils and the broth to a boil in a medium saucepan over high heat. Reduce heat to medium-low, partially cover and simmer until the lentils are fully softened and the liquid is absorbed, about 30 minutes. Transfer to a medium bowl with the remaining 1 tablespoon broth and mash well with a potato masher. Set aside.
- Heat the oil in a large nonstick skillet over medium heat. Add the chopped onion, lemon juice and cook, stirring, until softened, about 6 minutes. Add the spinach, garlic, 1 1/2 teaspoons black pepper and cumin and stir until the spinach is wilted, about 3 minutes.
- Add the spinach mixture, walnuts to the lentils and mix thoroughly. Cover and refrigerate for at least 1 hour or overnight.
- Preheat the grill to medium-high. Form the mixture into two patties and spray with cooking spray on each side. Grill until nice grill marks form, about 3 minutes per side. Place the patties in the buns with the sliced onion and other toppings, as desired, and serve.