Put juice and sugar into a saucepan and bring to boil, then simmer for 15-20mins to let the liquid reduce. Set aside to cool. Transfer syrup to a sterilised jar.
Fill a pint glass full of ice and pour ice into a zip seal food bag. Crush with a rolling pin.
Next, fill a rocks glass with crushed ice. Add Raspberry Vodka, lime juice and 5ml of the syrup. Stir with a chopstick. Add more ice to the top of the glass and garnish with the bruleed lime halves and a raspberry.
To brulee the limes, cut the limes into half or wedges. Pat dry with kitchen paper and leave to dry out for 10 mins. Sprinkle with sugar and then brulee with a blow torch. Alternatively simply put under a grill. Set aside to cool before using as a cocktail garnish.
To finish your cocktail drizzle the remaining syrup with a spoon over the top of the ice, creating a bleeding effect through the drink.