Riffing off of Keller's Under Pressure, I pickled a bison tongue about six weeks ago. I had to look at that ugly thing for six long weeks, all along hoping it was staying edible and not knowing if it would be any good at all.
After I removed it from the brine and dried the tongue I set about to clean it.
Trimmed some edges, removed the skin and membrane, cut it in half to make it easier to work with.
Then ran it through my slicer to get it as thin as I could.
Next, I took some day old brioche and lined an 8x8 pan snugly.
Soaked the brioche with a savory custard.
Added a layer of overlapping tongue slices.
More brioche, more custard and then baked til puffed, set and brown.
Following Keller's lead I chilled the pain perdu, then used a 3" round cutter to cut crescents which were browned in a skillet with butter and held til service. At service they got 5 minutes in a 350º oven to warm. Very, very good stuff. Too bad you have to plan so far in advance.