1. Toast the rice in a saucepan with 10g butter. Add hot stock and saffron, and stir occasionally.
2. In a separate pot, sweat the onions in 10g of butter. Add the wine and reduce the liquid by half, then add
the remaining butter, small nuggets at a time. Mix with a whisk until the butter becomes smooth (beurre blanc). Filter the butter through a strainer to remove the onion.
3. When the rice is cooked, season with salt and mix the beurre blanc and grated Parmigiano into the rice. Serve with a piece of gold leaf atop each portion.