How to Make It
Melt the butter in a large skillet. Add the onion and cook over moderate heat, stirring occasionally, until softened, about 4 minutes. Add the fennel and leeks and cook over moderately high heat, stirring frequently, until the vegetables are sizzling and lightly browned, 13 to 15 minutes. Add the wine and cook, stirring, until nearly evaporated. Remove from the heat and stir in the cheese until melted. Add the dill, season with salt and pepper and serve.