Squash Blossoms Stuffed with Ricotta

INGREDIENTS

• 1/4 teaspoon hot red pepper flakes
• 2 tablespoons olive oil
• 1 garlic clove, minced
• 12 to 16 large zucchini squash blossoms
• About 3 cups vegetable oil for frying
• 3/4 cup chilled seltzer or club soda
• 1/4 cup finely chopped mint
• 1/2 teaspoon sugar
• 1 1/2 pound plum tomatoes, finely chopped
• 1/2 cup plus 1 tablespoon all-purpose flour
• 1 large egg yolk
• 1 cup whole-milk ricotta (preferably fresh)
• 1/2 cup water
• 2/3 cup grated Parmigiano-Reggiano, divided