It may not be traditional, but I can tell you how it tastes: phenomenal. The assembly goes like this: roll out your puff pastry to about 1/4″ thickness and cut out your crusts. You want the circles to be as big around as the outside lip of the ramekin molds. Once they’re cut, store them in the refrigerator until needed.
Now for the caramel. Pour 4 tablespoons of sugar into a small saucepan, add a tablespoon of water and place it over high heat.
Swirl the pan gently until the mixture melts, bubbles and finally turns a medium-to-dark amber (for more detailed instructions on making caramel, see the tutorial under the Pastry Components menu to the right). Remove the pan from the heat and add a 1/4 teaspoon of sherry or red wine vinegar. It will bubble a little. Swirl to combine.
Spoon about a tablespoon of the caramel into each ramekin.
Add three olives and a roasted garlic clove to each.
Then insert a roasted tomato half, cut side up.
Next go the caramelized onions, about one and a half tablespoons.
Salt and fresh ground pepper.
Top it all off with a puff pastry round. Don’t worry if it sags in the middle.
Bake at 425 for about 20 minutes until nicely browned.
Let the tarts rest for about a minute before turning them out. Careful now, they’re hot. Turn them out by placing a small plate on the top of the ramekin (don’t worry if that crushes the pastry a little…you need a flat bottom anyway).
Using a towel, grasp the hot ramekin with one hand and the plate with the other and flip the whole thing over. Jiggle the mold a little to loosen the tart. If it doesn’t come out, try running a sharp knife around the edge of the tart and repeating the process.
Some caramel will run down the sides and pool on the plate. You can either serve the tarts as-is for a more rustic presentation, or re-plate them as I’ve done above. Garnish with a sprig of fresh thyme.