Volpi's Asparagus Risotto

Ingredients

• 4 cups low-sodium chicken broth
• 1 1/2 cups water
• 4 ounces pancetta
• olive oil
• 1 large shallot
• 1/2 teaspoon kosher salt
• 2 cups carnaroli or arborio rice
• 1/2 cup white wine
• 1/2 pound pencil-thin asparagus
• 2 tablespoons unsalted butter
• 1 large egg yolk
• 1/3 cup grated Parmesan
• freshly ground black pepper
• lemon zest