For the fritters:

• 10 ounces baby spinach leaves, rinsed well and drained
• 3 medium white onions, finely chopped (about 2 ½ cups)
• 1 cup + 2 tbsp olive oil
• 1 cup finely chopped dill leaves
• ¼ cup finely chopped flat leaf parsley
• 8 large eggs
• 1 ¼ cups white flour
• 3 cups coarsely grated Greek kefalotyri cheese or other sharp, hard cheese such as Parmesan
• 1 tsp salt
• freshly grated black pepper

For the tzatziki sauce:

• 2 cups Greek-style whole milk yogurt (or combination of 1 cup whole milk yogurt + 1 cup of leban, a strained, thickened Middle Eastern style of yogurt)
• ½ cup sour cream
• ½ tsp kosher salt
• 2 tsp very finely chopped or crushed garlic
• 2 Tbsp very finely chopped fresh dill
• pinch freshly ground black pepper
• 2 Tbsp white wine vinegar
• 2 Tbsp freshly squeezed lemon juice
• 2 Tbsp extra-virgin olive oil + extra, to serve
• 1 Kirby cucumber, peeled, coarsely grated and drained of excess water