Step 1

Preheat the oven to 400F. Lightly coat a 12-cup muffin tin with spray oil.

Step 2

In a bowl, add all of the herb oil ingredients and stir until combined. Set aside.

Step 3

Ideally using a mandolin, slice the sweet potatoes and Yukon gold potatoes 1/16th of an inch thick. Put the sweet potatoes in one bowl, and the Yukon golds in another.

Step 4

Split the herb oil between the two bowls, and coat the potato slices.

Step 5

In each muffin cup, add a sprig of thyme, followed by the sliced potatoes. I make one muffin cup yukon gold, and the next sweet potato. These don't have to look perfect. Stagger the potato slices for good looking stacks, and fill the muffin tins completely as the potatoes will shrink in the oven.

Step 6

Add flakey salt on top, and cover with foil. Place in the oven for 20 minutes. Remove the foil, and bake for an additional 20 to 25 minutes, until the stacks are crispy. You can broil on high for 2 to 3 minutes at the end, watching closely, to get the crispy stacks you desire.

Step 7

Enjoy with more thyme and flakey salt as desired. This is the perfect holiday side dish!