Combine yoghurt and ½ tsp sea salt in a bowl, transfer to a sieve lined with muslin, place over a bowl and refrigerate overnight to drain (discard liquid).
Cook half the butter in a small saucepan over medium-high heat until foaming and starting to turn golden (1-2 minutes), add sage and stir occasionally until crisp (20-30 seconds). Drain and reserve leaves and butter separately.
Heat oil and half the remaining butter in a large wide saucepan over medium-high heat, add onion, stir occasionally until translucent (3-4 minutes). Add rice, stir until grains become transparent (1 minute), deglaze with wine and cook until wine evaporates (1-2 minutes), then add pepper. Add stock, a ladle at a time, stirring continuously until stock is almost completely absorbed and rice is tender (16-18 minutes). Remove from heat, season to taste, stir in parmesan, sage butter and remaining chopped butter, cover and stand for 3 minutes, then serve hot with dollops of drained yoghurt, scattered with crisp sage.
This recipe is from the May 2012 issue of Australian Gourmet Traveller.