This recipe can be made through step 2 up to 3 days in advance.
- 1 cup granulated sugar
- 1 cup water
- 1 medium, ripe peach (about 6 ounces)
- 1/2 pint fresh raspberries (about 6 ounces)
- 1 bunch fresh lemon thyme (about 30 sprigs), rinsed and woody ends trimmed
- 1 liter cold club soda
- Bring the sugar and water to a simmer in a small saucepan over medium-high heat, stirring occasionally until the sugar has dissolved, about 5 minutes. Remove from heat and let cool to room temperature. Transfer the syrup to a small container with a tightfitting lid.
- Halve, pit, and cut the peach into 1/8-inch-thick slices. Add the peach slices to the syrup and stir to combine. Seal the container and refrigerate until the peach flavor infuses the syrup, at least 4 hours or up to 3 days.
- When ready to serve, pour the syrup through a fine-mesh strainer set over a medium bowl; discard the peach slices. Add half of the raspberries and half of the thyme sprigs to the bowl. (Set the other half of the raspberries and thyme aside for garnish.) Using a potato masher, briefly smash the raspberries until they release their juices.
- Set a fine-mesh strainer over a large pitcher and pour in the raspberry mixture. Lightly press on the solids with a rubber spatula, then discard the contents of the strainer. Add the club soda and some ice to the pitcher and stir gently with a long spoon until combined.
- Gently bruise the remaining half of the thyme by crushing it in your hands (but don’t completely mangle it) and set it aside. Pour the Peach Melba Cooler into ice-filled collins glasses and garnish each drink with a sprig of the thyme and a few fresh raspberries.