Method:

1. First prepare the sauce, so that it has time to infuse while you prepare the blossoms. Finely mince the basil leaves, either by hand with a knife or in a food processor. Combine the minced leaves with the yogurt in a bowl, cover with plastic film and place in the fridge to infuse. 
2. Remove the stamen from the inside of the zucchini blossoms. To do this, gently pry open the top of the blossom, reach inside with your fingers and pinch the stamen, then pull it out carefully. Set the blossoms aside.
3. Prepare the filling in a bowl. Finely mince the mint leaves, and then mix them into the ricotta. 
4. Position the blossom base carefully inside your palm and hold the petals open with your thumb and index finger of the same hand. With the other hand, carefully spoon the ricotta stuffing into the blossom. Once each blossom is filled, pin the tops shut with two toothpicks, crossing over one another diagonally. 
5. Heat a layer of sunflower oil in a thick-bottom pan.
6. Prepare the frying batter by combining the flour, salt and sparkling water and mixing together. Roll the blossoms in the batter and transfer to a plate, ready to fry. 
7. Place the blossoms in the batter and then flip them once sufficiently browned on one side, and then the other. 
8. Serve on a bed of zucchini tartare, if your blossoms came with them. Otherwise, enjoy as is with the sauce.