Place 1/4 cup balsamic vinegar in a pan on medium heat. Simmer around 5 to 6 minutes until it thickens and reduces in half to around 2 tablespoons.It should be thick and coat the back of a spoon.
Transfer this to a bowl or measuring jar. Add olive oil, maple syrup, garlic powder, black pepper and salt to taste. Mix everything and set aside.
Meanwhile place 1/2 cup pecans (or 3/4 cup if you like more nuts) in a pan on medium heat. Roast for 7 to 8 minutes, stirring often (else nuts will burn) until browned and toasted.Then chop the pecans into bite size pieces.
To a large bowl, add arugula, chopped mangoes, toasted pecans. Drizzle the dressing and mix.Serve the mango arugula salad immediately. You can also add some goat cheese on top before serving.
You can use honey in place of maple syrup.
Be careful with the balsamic vinegar, it shouldn't clump up. Stir often and boil only until it thickens and coats the back of a spoon.