Heat oven to 400 degrees

Use a mandolin, slice potatoes into paper thin circles

Par cook potatoes in boiling water for about 15 minutes (potato is par cooked when it's firm but still bendable) pat dry thoroughly with a towel ensuring all water is absorbed

In an 8inch cast iron skillet or casserole dish, assemble potatoes into even layers being sure to overlap each potato slice

Once the potatoes are assembled, warm the heavy cream in a sauce pan until it's steaming (not boiling) and butter, herbs, garlic and better than boullion

Once butter has melted, turn off the heat and pour mixture over the potatoes discarding of the thyme stems

Cover the potatoes with foil and bake for 20 minutes, then remove from the oven carefully and add crab and shrimp in an even layer and then add cheese as the last layer

Increase heat to 450 degrees and bake for an additional 15-20 minutes until cheese is melted, potatoes are fork tender and seafood is cooked

Seafood gratin is done when the liquid has absorbed, potatoes are fork tender and cheese has melted and is golden brown on top

Remove from heat and allow the gratin to cool and set for an additional 10 minutes before serving