Put the brie on a serving plate that can accommodate the brie plus the liquid from the peaches.
In a small microwave-safe bowl, warm the jelly until it has liquifies, about a minute.
Cut the peach flesh away from the pit and coarsly chop. Toss the peaches and any accumulated juice with the pepper jelly. Garnish wiht basil if using.
Top the brie with the peach mixture and serve with crackers.