Preparation Toss zucchini and 1/2 teaspoon salt in large bowl. Let stand 5 minutes. Transfer to sieve. Press out excess liquid; place zucchini in dry bowl. Mix in egg, yolk, 1/2 cup flour, cheese, and 1/2 teaspoon salt. Mix in parsley, onions, and dill. If batter is very wet, add more flour by spoonfuls. Heat 2 tablespoons olive oil and 2 tablespoons corn oil in large skillet over medium heat. Working in batches, drop batter by rounded tablespoonfuls into skillet. Fry patties until golden, 5 minutes per side, adding more olive oil and corn oil as needed. Transfer to paper towels. DO AHEAD Can be made 1 day ahead. Place on baking sheet, cover, and chill. Rewarm uncovered in 350°F oven 12 minutes. Serve with yogurt.
Preparation Toss zucchini and 1/2 teaspoon salt in large bowl. Let stand 5 minutes. Transfer to sieve. Press out excess liquid; place zucchini in dry bowl. Mix in egg, yolk, 1/2 cup flour, cheese, and 1/2 teaspoon salt. Mix in parsley, onions, and dill. If batter is very wet, add more flour by spoonfuls. Heat 2 tablespoons olive oil and 2 tablespoons corn oil in large skillet over medium heat. Working in batches, drop batter by rounded tablespoonfuls into skillet. Fry patties until golden, 5 minutes per side, adding more olive oil and corn oil as needed. Transfer to paper towels. DO AHEAD Can be made 1 day ahead. Place on baking sheet, cover, and chill. Rewarm uncovered in 350°F oven 12 minutes. Serve with yogurt.