- A handful of walnut halves (about 3-4 tablespoons)
- 3 tablespoons extra virgin olive oil (EVOO), divided
- 1/2 small red onion, finely chopped
- 1/3 cup whole milk
- 2/3 cup feta crumbles
- 1 tablespoon fresh marjoram or oregano, chopped or 1 teaspoon dried, divided
- A few sprigs of mint, leaves chopped
- Salt and freshly ground black pepper
- 1 1/2 pounds ground lamb
- 1 teaspoon paprika or smoked paprika
- A couple pinches of ground cinnamon
- 1 clove garlic, crushed
- 2 bunches farm spinach leaves, stemmed, washed and dried
- Freshly grated nutmeg
- Ciabatta rolls or sliced crusty bread, toasted
Toast the walnuts in a dry skillet over medium heat. Remove to a plate and set aside.
Add 1/2 tablespoon EVOO, half a turn of the pan, and the onion. Cook for 5 minutes to soften, then put the onion in a mixing bowl to cool.
While the onion cools, put the milk, feta, half of the marjoram or oregano, mint, salt and pepper, to taste, and the nuts in a food processor and process into a thick, smooth sauce.
Add the lamb to the bowl with the onion and season with salt and pepper, to taste. Stir in the remaining marjoram or oregano, paprika and cinnamon. Form the mixture into four patties, thinner at the center and thicker at the edges so that they don't bulge when cooking. Heat 1/2 tablespoon EVOO in nonstick skillet over medium-high heat and cook the patties for 3-4 minutes on each side for pink centers.
Meanwhile, heat 2 tablespoons EVOO in another skillet over medium-low heat. Add the garlic and let it infuse the oil for 1-2 minutes. Add the spinach and let it wilt, then remove the pan from the heat and season with salt, pepper and nutmeg, to taste.
Add the lamb patties to the bun bottoms or toasted bread. Shake off any excess liquid as you remove the spinach and pile it on top of the burgers. Slather the bun tops with the feta sauce. Cover the burgers with the bun tops and serve.