Roast almonds in a medium skillet over medium-low heat, shaking until nuts are fragrant and toasted, about 8 minutes. Let almonds cool, then coarsely chop.
Melt butter in same skillet; add brown sugar and lemon juice and cook, stirring constantly with a fork, until melted and smooth. Add cranberry-raspberry juice and bring to a boil over medium-high heat. Cook until reduced by half, remove from heat and add raspberries. Stir gently for 1 to 2 minutes, until berries are warm and sauce is cooled slightly.
Scoop ice cream into ice cream bowls or parfait glasses, spoon sauce on top, and sprinkle with toasted almonds and chocolate shavings.