*optional: Serrano ham (if you leave this out, the dish is vegetarian)
Defrost puff pastry on counter (15 min)
Preheat the oven to 400F. Remove the stems from the figs and cut them in half. Place figs on a sheet pan and sprinkle with a touch of olive oil and brown sugar. Roast in the broiler for 20 minutes or until the interior is brown and figs have crisp, golden edges. There are nine tartlets and 10 fig halves. Snack on the extra fig.
Cut puff pastry sheet into 9 equal squares and dock each piece with a fork. Place each piece over an upside down non-stick cupcake tin. Bake in the same 400F oven for 8 minutes or until golden. Cool on a baking rack for 20 minutes.
While figs and puff pastry are baking, slice up the onions and garlic into thin strips. In a cast iron skillet, heat up a bit of olive oil and add in onions and garlic. Stir to coat in oil and let them cook over medium heat until they get a bit of color. Reduce heat and continue cooking until onions are soft. Then sprinkle in a bit of brown sugar for added color and sweetness. Cook until the sugar is dissolved and the onions are caramelized. Let onions cool.
Heat 1/4 cup vinegar and 2 tablespoons of brown sugar over low heat until it bubbles furiously and forms a thick syrup (consistency of chocolate syrup).
To assemble the tartlet, smear about 1 tablespoon of goat cheese in each tartlet. This is optional (without it the dish will be vegetarian) add a small piece of thinly sliced Serrano ham. Then pile on good spoonful of caramelized onions. Place a fig on top. Finally drizzle with the balsamic vinegar reduction.