2 tablespoons chaat masala
2 tablespoons cumin seeds, toasted and ground
1 tablespoon red chili powder
1 tablespoon dried mint
1 cup buttermilk
1 tablespoon tandoori masala
2 large yellow onions, peeled, cut into 1/8-inch-thick rings
Vegetable oil, for frying
2 cups all-purpose flour
Kosher salt