Cut potatoes into ⅛” slices. In a baking dish, layer potatoes in a shingle-like pattern and stand them up slightly. Season potatoes with 1 Tbsp Butcher’s Blend, making sure to separate potatoes to season in between them.
In a saucepan over medium heat add 2 Tbsp olive oil and shallots, cook 2-3 minutes until shallot is soft.
Add 2 Tbsp of flour and cook for another 2 minutes to remove the flour flavor. Slowly add milk while whisking constantly. Season with 2 tsps Butcher’s Blend, vinegar, and 1 cup cheese, stirring until cheese is melted.
In a small bowl combine bread crumbs, ½ cup cheese, and rub. Crumble panko mixture over gratin.
Bake for 45 minutes or until potatoes are tender and slightly browned.