How to Make It
Heat the butter and 1 tablespoon of the oil in a saucepan over medium heat. Add the onion; cook 5 minutes. Add the rice and cook, stirring constantly, 2 minutes.
Reduce heat to medium-low. Add the wine and cook, stirring frequently, until absorbed. Add the broth, ½ cup at a time, stirring occasionally and waiting until it’s absorbed before adding more. This should take about 30 minutes. The rice should be tender but still slightly firm.
Meanwhile, about 5 minutes before the risotto is done, heat 2 tablespoons of the oil in a skillet over medium heat. Add the radicchio and garlic. Cook, stirring occasionally, until the radicchio is browned and slightly wilted, about 5 minutes. Add the oregano (if desired), vinegar, and ¼ teaspoon salt. Transfer to a plate.
Remove the risotto from heat and stir in the Parmesan, remaining salt, and pepper. Cover to keep warm.
Wipe out the skillet, return to medium heat, and heat the remaining oil. Add the bread crumbs and cook until golden brown, 2 to 3 minutes.
Spoon the risotto into individual bowls and top with the radicchio and bread crumbs.