This is one of the most delicious salads I have ever eaten, but please do not skip the sumac. It's a middle eastern spice that's hard to substitute.
Ottolenghi's Spinach Salad with Dates, Almonds, and Pita
1 tablespoon white wine vinegar
1/2 medium red onion, thinly sliced
3 1/2 ounces dates (100 grams or 5-6 dates),preferably Medjool, pitted and quartered lengthwise
2 tablespoons unsalted butter (30 grams)
2 tablespoons olive oil, divided
2 small pitas (about 3 1/2 ounces, or 100 grams), roughly torn into 1 1/2 -inch pieces
1/2 cup whole unsalted almonds (75 grams), coarsely chopped
2 teaspoons sumac
1/2 teaspoon chile flakes
5 to 6 ounces baby spinach leaves (150 grams)
2 tablespoons freshly squeezed lemon juice
Put vinegar, onion and dates in a small bowl. Add a pinch of salt and mix well with your hands. Leave to marinate for 20 minutes, then drain any residual vinegar and discard.
Meanwhile, heat butter and 1 tablespoon olive oil in a medium frying pan over medium heat. Add pita and cook for 4 to 6 minutes, stirring all the time, until pita is golden. Add almonds and continue cooking until pita is crunchy and browned and almonds are toasted and fragrant, about 2 minutes more. Remove from heat and mix in sumac, chile flakes and 1/4 teaspoon salt. Set aside to cool.
When ready to serve, toss spinach leaves with pita mix in a large mixing bowl. Add dates and red onion, remaining 1 tablespoon olive oil, the lemon juice and another pinch of salt. Taste for seasoning and serve immediately.