For the sun-dried tomato jam:
Place a medium saucepan over medium heat. Add the chopped sun-dried tomatoes, 1 tablespoon of the reserved sun-dried tomato oil, olive oil, onion, and garlic. Stir and cook until the onions are soft and beginning to brown at the edges, about 5 to 7 minutes. Add the sugar, vinegar, water, chicken broth, thyme, salt, and pepper. Bring the liquid to a boil, reduce the heat, and simmer, covered, for 30 minutes. Remove the cover and continue simmering until most of the liquid is reduced and the mixture is the consistency of jam, about 5 to 10 more minutes. Remove from the heat and set aside.
For the crostini:
Preheat the oven to 400 degrees F. Line a baking sheet with foil.
Place the baguette slices on the baking sheet. Using a pastry brush, lightly coat the baguette slices with olive oil. Sprinkle with salt and pepper. Bake until lightly toasted, about 8 minutes.
Place the soft goat cheese in a small bowl. Stir in the thyme.
Spread the crostini with sun-dried tomato jam and top with the goat cheese and herb mixture. Transfer to a serving plate and serve.