Cut your bread in half the long way. I like to leave one of the sides uncut (like they do at subway), so the filling doesn’t spill out everywhere.
Spread 2 tablespoons of the garlic/herb spread on each piece of bread.
Layer on a scoop of the caramelized onions (use half per sandwich).
Carefully place your mango and 3 slices of brie inside the sandwich. I prefer to push these deep into the sandwich (towards the uncut) end because they will pop out when you press it.
Place your Mango Brie Panini into a panini press or George Foreman Grill and wait about 5-10 minutes. You will know the panini is done when the brie is melted, the sandwich is nearly flat and the bread is crunchy.