use a mandolin to slice sweet potatoes into 1/10-⅛ inch thick slices. Pour melted butter over and toss with your hands to coat. Set aside
To make the pecan crumble, combine pecans, flour, cinnamon, brown sugar, with melted butter. Stir until evenly mixed.
Spray a muffin tin with non stick spray. Begin forming your sweet potato stacks. Fill the muffin tin half way with sweet potatoes then add a layer of pecan crumble. Add more sweet potatoes until it is filled to the top then add more pecan crumble on top. Repeat until you have used up all the potatoes.
Stick a tooth pick through the stack to keep everything together and compacted
Transfer to oven and bake for 30 minutes
Notes
If you are not making these for a crowd and want a slightly less messy option, you can also cook these in small, 4 oz, ramekins. Same baking time applies.