Roasted Sweet Potato Salad

Name: Roasted Sweet Potato Salad
Ingredients: Vegetable spray; 4 Small sweet potatoes, peeled and cut into 1-inch cubes; 1 Large yellow onion, peeled and cut into eighths; 2 tablespoons Olive oil; 1 teaspoon Kosher salt; 1 teaspoon Freshly ground black pepper; 1/4 teaspoon Garlic powder; Vinaigrette:; 1/4 cup Balsamic vinegar; 2 teaspoons Maple syrup; 1 Clove, finely chopped garlic; 1/2 teaspoon Salt; 3/4 cup Fine olive oil; 1 teaspoon Fresh Lemon thyme, finely chopped; 1 teaspoon Fresh chives, finely chopped; 1 teaspoon Fresh Sweet marjoram, finely chopped