Simmer stock in a small pot over medium heat.
Set a high-walled sautée pan over medium heat. Melt butter and sautée onions until they are soft and translucent.
Pour rice in and sautée until the rice starts to sound like glass beads. If the rice starts to turn a little tan, that's ok, but move on to the next step to avoid burning. Do not add salt or pepper until the end.
Pour wine in to deglaze the pan and stir until all of the wine has absorbed into the rice.
Add about 6 ounces of broth to the rice with a ladle and stir until the liquid has absorbed to the point where you can part the risotto down the center with your spoon, and it stays parted.
Add 4 ounces of broth to the rice and stir until liquid has been absorbed and you can part the risotto. Repeat this process about three more times. At this point, you need to start tasting the risotto. If it is crunchy in the middle or a bit too al dente, add more liquid. As it starts to get closer to the texture you desire, add less and less liquid.
Once it has reached your desired texture, remove from heat and stir in your cheese until it is fully combined and melted.
Taste your risotto. If it seems too salty or one-dimensional, add a squeeze of lemon or some lemon zest. You could also stir in a little bit of wine instead. At this time, also stir in any salt or pepper you might want.
Plate your risotto and finish with fresh black pepper, cheese and lemon zest.
