1/4 cup farro
1 pound sunchokes, peeled and cut into 2-inch pieces
1 bunch kale, tough stems discarded
3 tablespoons olive oil
1/3 small red onion, sliced 1/4 inch thick
1 teaspoon unsalted butter
1/4 pound oyster mushrooms, halved if large
Freshly ground pepper
Serves 2-4