To make the coulis, place the raspberries, lemon juice, sugar and liqueur in the bowl of a food processor and process at high speed until very smooth. Pass through a fine sieve and pour into a large squeeze bottle. Refrigerate until ready to use (for up to 3 days).
To serve, squeeze a little raspberry coulis into a martini glass. Top with one or two scoops of ice cream, depending on the size of your glasses. Garnish with the fresh raspberries. Top each glass with sparkling cider at the table. Watch it fizz, and enjoy!