The day before, drop a whole raspberry into each cavity of an ice cube tray, fill with water, and freeze until solid, at least 4 hours.

Combine 2 cups raspberries, the sugar, and 2 tablespoons water in a small saucepan over medium heat.

Simmer, mashing the berries with a spoon, until the mixture thickens slightly and coats the back of the spoon, about 5 minutes.

Strain the raspberry syrup through a fine mesh sieve into a bowl, pressing on the seeds, then discard the solids and let the syrup cool.

In a large pitcher, stir the cooled raspberry syrup into the lemonade until the color turns deep pink.

Fill glasses with the raspberry ice cubes.

Pour the raspberry lemonade over the ice, filling each glass about two-thirds full.

Top with club soda, stir once gently, and serve while the ice cubes are still bright with fruit.