Prepare the Strawberry Simple Syrup: In a small saucepan, combine 1 cup of water, 1 cup of granulated sugar, and 1 cup of sliced fresh strawberries. Bring to a simmer over medium heat, stirring occasionally until the sugar is dissolved and the strawberries are soft, about 5 minutes. Remove from heat and let it cool completely. Strain the syrup to remove the strawberry solids, and store it in the refrigerator until ready to use.

Muddle the Strawberries: In a cocktail shaker, muddle 3 fresh strawberries until they release their juices and are well mashed.

Add the Liquids: To the shaker, add vodka, elderflower liqueur, fresh lemon juice, and 1 oz. of the prepared strawberry simple syrup.

Shake It Up: Fill the shaker with ice cubes, then cover and shake vigorously for about 15 seconds to chill the mixture.

Strain Into Glass: Strain the cocktail into a glass filled with ice cubes.

Top with Soda Water: Top up the glass with soda water to your liking.

Garnish: Garnish with a fresh strawberry on the rim of the glass.

Serve and Enjoy: Serve immediately and enjoy the refreshing taste of summer!