Zucchini Flowers with Ricotta, Parmesan, and Anchovy Sauce

Ingredients

• 280 gm tempura batter flour, sieved (see note) (2 cups)
• 375 ml soda water (1½ cups)
• 15 zucchini flowers, ends trimmed
• For deep-frying: vegetable oil
• For dusting: plain flour
• 4 eggwhites, whisked to soft peaks
• Ricotta stuffing
• 200 gm firm ricotta
• 50 gm Grana Padano, finely grated
• 60 gm soft goat's cheese
• 1 cup mint, finely chopped (loosely packed)
• Mint and anchovy sauce
• 3 cups mint, finely chopped (firmly packed)
• 125 ml extra-virgin olive oil (½ cup)
• ¾ cup flat-leaf parsley, finely chopped (firmly packed)
• 2 tbsp capers in vinegar, rinsed, drained and coarsely chopped
• 5 anchovy fillets, finely chopped
• Juice of 1 lemon, or to taste