Melt 25g of butter in a large pan and fry the onion and garlic for 3 minutes.
Stir in the Arborio rice to coat it thoroughly in the butter.
Cook the rice for 2 minutes until translucent then add wine and evaporate liquid.
Gradually add stock one ladle at a time until the rice is al dente.
Fold in the courgette, mascarpone, 25g of parmesan, and remaining butter.
Season the risotto with salt and pepper.
Heat oil in a deep pan or fryer to 190°C.
Fill courgette flowers with a mixture of ricotta, lemon zest, and lemon juice.
Whisk yeast, salt, sugar, tonic water, flour, vodka, and vinegar into a bubbly batter.
Dip flowers in batter and deep-fry for 2 minutes before draining on kitchen paper.
Blend basil and olive oil until smooth then pass through a sieve.
Serve risotto topped with fried flowers, basil oil, and extra parmesan.