Easy Vegan Mushroom Crostini

Name: Easy Vegan Mushroom Crostini
Prep time: 10 min
Cook time: 20 min
Total time: 30 min
Cuisine: American, European
Ingredients: 2 tablespoons olive oil (divided); 1 large onion; 1 teaspoon sugar; ½ teaspoon salt; 2 tablespoons balsamic vinegar; 1 lb or 450 g cremini mushrooms (or other mushrooms of your choice (see notes)); 3-4 sprigs thyme (divided (or 1 teaspoon dried thyme + 1 sprig fresh thyme to garnish)); 2-3 cloves garlic (minced); ½ crusty baguette (can be stale, see notes); ¾ cup vegan mozzarella shreds (for alternatives, see notes); Salt and freshly ground black pepper to taste; 1 teaspoon Maille Dijon Originale Mustard; 2 tablespoons extra virgin olive oil; 1 tablespoon balsamic vinegar