Preheat oven to 350 degrees Fahrenheit and grease muffin tins.
In large bowl, mix all ingredients for the pupcakes. Form the mixture into balls and lightly press them into each cup.
Bake for approximately 20 to 30 minutes.
While the pupcakes are in the oven, make your topping. Set aside until pupcakes are ready.
Scoop the mashed potatoes on top of the pupcakes and garnish with thyme.