Beet Fritters With Beet Greens Yogurt

Name: Beet Fritters With Beet Greens Yogurt
Ingredients: 4 medium beets with greens (about 1 lb.); 1 large or 2 medium Yukon Gold or russet potatoes (about 10 oz.); 1 medium onion; 1½ tsp. kosher salt, plus more; 4 Tbsp. (or more) extra-virgin olive oil, divided; 2 large eggs, beaten to blend; 6 Tbsp. panko; ¼ cup cornstarch; 2 tsp. coriander seeds, crushed; 2 tsp. cumin seeds, crushed; 1 lemon, halved; ½ cup plain whole-milk yogurt; ½ cup coarsely chopped dill; Freshly ground black pepper