Whisk the egg with vinegar and 3 tablespoons of ice water and set aside. Follow instructions below, depending on if you want to make the crust by hand, or if you want to use a food processor.

MANUAL METHOD: Mix together the flour, sugar, thyme, salt, garlic powder, and cream of tartar in a large wide bowl. Using a box grater, grate the butter using the large hole setting of the grater above the bowl, stopping to stir with a fork and coat the butter bits in the flour mixture every 10 seconds or so. When all the butter is in, pinch the mixture together with your fingertips until it resembles the texture of damp sand. Add the water, a tablespoon at a time, mixing it with a fork, until the dough just holds together when you squeeze a fistful of it in your hand.

FOOD PROCESSOR METHOD: Cut the butter into individual tablespoons and set aside. Place the flour, sugar, salt, sage, onion powder, and cream of tartar in the food processor and pulse a few times to mix together. Add the slices of butter and pulse until the butter is reduced to roughly pea-sized pieces. Run the machine while you add the egg mixture, letting it blend for 5 seconds after the liquid is added. Do NOT overmix. Add the remaining ice water, 1 tablespoon at a time, pulsing as you add it, until the dough just holds together. It shouldn't be too wet and sticky, nor should it be super crumbly. Wrap in beeswrap or plastic wrap, and place it in the refrigerator for 30 minutes.

Heat the olive oil in a medium-sized frying pan over medium heat. Add the onions and garlic and saute until transparent and lightly golden around the edges, stirring every few minutes. Add the pumpkin puree, salt, and spices and stir to combine. Cook to evaporate out some of the moisture from the pumpkin, about 5 to 7 minutes more, stirring every couple minutes. Remove from heat and allow to cool to room temperature and then place in the refrigerator to cool for an hour. Stir in crumbled goat cheese.

Preheat the oven to 350 degrees Fahrenheit. Roll out the dough until it is ⅛-inch thick. Use a leaf-shaped cookie cutter to cut out various leaf shapes (alternatively, you can draw a leaf shape on a piece of paper, cut it out, and use it as a tracing to hand-cut the lead shapes out with a knife).

Brush the borders of the leaves with the egg wash (this will help them form a tight seal later on). Use a spoon to scoop some of the filling into the center of half of the leaf cut-outs. The remaining leaves need to remain “blank” so that they can be the top of the hand pie. Spread the filling out to keep it relatively flat (if it’s domed it will be harder to affix the top layer of the leaf dough), but make sure to leave a border of empty space around the edges.

Cut some small vent slits into a blank leaf, placing them where the leaf’s veins might be, and then place the blank leaf on top of the filling leaf. Press down around the edges to seal them together. Place them on two baking sheets lined with parchment paper and bake until the crust is golden brown, about 25-30 minutes. Enjoy!