How to Make It
Lightly season the cod with salt; cover and refrigerate for 1 hour.
Meanwhile, in a food processor, combine the garlic and mint and process until finely chopped. Add the mayonnaise and pulse to blend. Scrape the mint aioli into a bowl and season with salt and pepper.
In a large saucepan, heat 2 inches of oil to 325°. Set a wire rack over a baking sheet. In a large bowl, whisk the 1 1/2 cups of flour with the Prosecco. Spread a handful of flour in a shallow bowl. Dredge each fillet in the flour, then dip into the batter to coat; let any excess drip back into the bowl. Working in 2 batches, carefully add the cod to the hot oil and fry, turning once, until browned and crisp, about 3 minutes. With a slotted spoon, transfer the cod to the rack to drain for 1 minute. Serve at once with the mint aioli and lemon wedges.