This gratin has a delectable cream sauce, tender leeks, and a crispy smokey topping!
Combine the topping ingredients together except the dill, and sprinkle over the top in an even layer.
If your dish is quite full to the top edge place a baking sheet on the bottom rack of the oven and place the gratin above on the middle rack. This will catch any bubbling sauce that might over flow. Bake for 30 minutes or until the top is golden brown and the sauce is bubbling.
Depending on your oven you might need to move the dish to the top rack for another 5 to 10 minutes to get the top more crispy and brown.