Raspberry Simple Syrup:

1. Heat the raspberries, sugar and water in a saucepan over medium to high heat. Stir occasionally. Use a fork to break down the raspberries, releasing their juices.
2. Continue to heat the syrup for another 5 to 7 minutes until the sugar has completely dissolved.
3. Once dissolved, remove the syrup from the stove and pass it through a fine mesh sieve to remove the raspberry chunks.
4. Let the syrup cool to room temperature before using in the cocktail.

Raspberry Gin Fizz:

1. Add the gin, lemon juice, raspberry simple syrup, and egg white to a cocktail shaker without ice. Shake well for 20 seconds.
2. Add in a handful of ice to the shaker and shake again for another 15 seconds until the outside of the shaker is frosted.
3. Strain and pour into a chilled Collins or coupe glass. Top with club soda. Garnish with fresh raspberries and serve.