In a small pot, combine split and scraped vanilla bean, sliced berries, sugar and liqueur or syrup. Place over low heat and let berries warm gently. In about 15 to 20 minutes, a thick sauce will form.
Scoop a big scoop of each flavor of ice cream into dishes. Pull vanilla bean out of sauce and pour the sauce over ice cream. Top ice cream with whipped cream and nuts and serve.
Recipe courtesy Rachael Ray