Heat 1 inch oil in a 3-quart wide heavy saucepan over moderate heat until it registers 375°F on thermometer. Working in batches of 3, dip blossoms in batter to coat, brushing them against side of bowl to remove excess batter, and fry, turning occasionally with a slotted spoon, until golden, 1 to 2 minutes per batch. Transfer to paper towels to drain and sprinkle lightly with salt. (Return oil to 375°F between batches.) Serve warm.