Preheat oven to 375* F.
Place the pie dough on a baking sheet and lightly fork the entire surface of the dough. Bake for 20-25 minutes until golden brown.
Place the tomatoes and asparagus on a baking sheet. Sprinkle the thyme leaves over the tomatoes. Drizzle 2 tablespoons of olive oil over the tomatoes and asparagus and season with salt and pepper. Bake for 10 minutes.
Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the onions and cook until golden brown, season with salt and pepper.
Spread the onion over the bottom of the tart shell. Arrange the tomatoes and asparagus slightly overlapping. Place the goat cheese on top of the tomatoes and asparagus. Place the tart into the oven for 5 minutes until the cheese starts to brown slightly.