Brush melted butter on the pineapple slices and grill evenly on both sides.
When just about to reach the end of grilling, brush the slices with liqueur or maple syrup.
Now remove the pineapple from the grill and cut into bite sized pieces.
Divide the pineapple pieces into separate bowls and top with dollops of vanilla ice cream.
Drizzle some more syrup on the ice cream and sprinkle the roasted nuts generously before serving.