Preheat oven to 350ºF

In a medium bowl, combine sweet potato, egg, butter, goat cheese, thyme, rosemary, salt, and pepper

Coat a muffin pan with non-stick cooking spray (I use Olive Oil)

Layer 5 phyllo sheets

Cut 2 5-inch circles from this stack of 5

Place layered phyllo circles into a muffin cup, ensuring that the phyllo is pressed firmly against the bottom and the sides

Repeat with remaining phyllo dough to create a total of 12 shells

Fill each shell with sweet potato mixture (do not overfill shells)

Bake at 350ºF for 20-25 minutes, or until phyllo is golden brown

Allow to cool before carefully removing each tart from the muffin pan