Step 1In a large saucepan, bring the stock to a simmer. Meanwhile, in a heavy pot over medium-high heat, gently saute the onions with the oil and one-half tablespoon of the butter, without browning them, 1 to 2 minutes. When the onions are soft and translucent, add the conserva and stir for a minute or two. Add the rice and stir well to coat.
Step 2Add the broth a ladle at a time, stirring constantly. When all the liquid is dissolved, add another ladle. Continue until the rice is done. It should be tender but still offer a slight resistance to the tooth.
Step 3When the rice is fully cooked, after about 35 minutes total cooking time, stir in the parmigiana, remaining butter, salt and pepper, and serve immediately. For optional garnish, top each serving with a dollop of conserva. Sprinkle with parsley.