Heat butter and oil in a wide, deep skillet until warm and add onions, salt and pepper. Cook over medium-high heat for a few minutes until softened and translucent.
Add the rice and stir to coat every grain. Cook the rice over medium heat for 3-4 minutes until the grains look more opaque.
Add 1 cup of the simmering stock to the rice and stir constantly until it’s almost absorbed. This will take about 5 minutes.
In 1 cup increments, same as the previous step, add 5 more cups of stock, allowing each cup to absorb before adding the next.
Once 6 cups have been added (this will take 20-30 minutes) taste the rice for salt and texture. Add some salt if necessary. If the rice is still a little too chewy, add another 1/2 cup of stock. (Note: this is also when you will add optional sauteed vegetables.)
Add the rest of the stock in 1/2 cup increments, same as before, but this time taste the rice frequently to test for doneness. When it’s properly cooked, the risotto should be tender without being soft, and moist not dry.
Remove from heat and add another tablespoon or two of butter and the Parmesan. Serve right away.
Leftover risotto can be spread into a pan and cooled. Once cool, it will solidify enough to cut into squares and the squares can be fried in butter to reheat and get crispy.