Black Trumpet, Potato, Yam Gratin

The technique of making a gratin is a simple one to master.   In the winter months, the thought of a bubbling, rich gratin with a crusty layer crowning the top makes me happy.

While I enjoy cheesy, creamy gratins, I tend to gravitate toward gratins simmered in rich, simply flavored stocks.

Over the holidays, I made a few renditions of a potato, yam and black trumpet mushroom gratin.  In one version, I thinly sliced disks of peeled yukon gold potatoes and yams and lined  them into layers in a baking dish.  Each layer was seasoned with salt, pepper and a few ladles of a black trumpet mushroom infused stock.

Other than slicing the yams and potatoes, the only other preparation is in creating the stock. Slice 1/4 lb of mushrooms (black trumpets are a very flavorful variety and a personal favorite) and saute in butter.  Let them simmer in about 5 cups of stock (along with some whole rosemary) for about 15 minutes on low heat.  The stock will now be fully flavored with earthy mushrooms.  On one occasion, I whisked in about 1/4 stick of butter to finish the stock.  On another, I whisked in about 1/4 cups of soft tallegio cheese and a touch of cream.   Both were excellent, but the tallegio version was phenomenal.

The stock is ladled to cover each layer of potatoes and yams that you can stand to slice.  I used a  mandolin on one occasion and therefore made my task simpler.  But I also used a knife in one instance and was able to get through the prep in about 15 or 20 minutes.  It's important to get your slices thin and as even in thickness as possible.  Each layer of yam and potato is seasoned, dotted with mushrooms and just barely covered in the stock.  Let this bake in a 350 oven for about 40-45 minutes, until the potatoes are soft and tender.  Sprinkle the top with bread crumbs and broil until golden. 

I've served this gratin with my favorite crusted pork recipe, as a side to whole red snapper and smoked paprika dusted lamb chops (above).

As you can see in this lamb dish, I was able to use a few tablespoons of the liquid remaining in the gratin as an added sauce bonus.