Strawberry Basil Tonic Recipe

Combine and simmer

In a small saucepan, add the quartered strawberries, chopped basil leaves, granulated sugar, and water. Stir to combine.

Cook gently

Place the saucepan over medium heat. Bring to a gentle simmer, stirring occasionally so the sugar dissolves. Once simmering, reduce heat to low and cook for 6–8 minutes until the strawberries are very soft and the liquid is fragrant with basil.

Macerate and mash

Remove the pan from heat. Use a fork or potato masher to gently mash the strawberries in the syrup to release more juice and flavor — about 30–45 seconds. Allow the mixture to sit for 5 minutes off heat so basil infuses further.

Strain

Place a fine-mesh sieve over a heatproof bowl or measuring cup. Pour the strawberry-basil mixture through the sieve, pressing on solids with the back of a spoon to extract as much syrup as possible. Discard solids (or reserve for another use). You should have approximately 1 cup of syrup; if you have more, reserve extra for later.

Finish with lemon

Stir the fresh lemon juice into the warm syrup to brighten flavors. Taste and, if needed, add up to 1 teaspoon more lemon for balance. Let the syrup cool to room temperature, then chill in the refrigerator for at least 20 minutes before assembling drinks.

Prepare glasses

Fill four tall glasses or two large glasses with the ice cubes, dividing ice evenly.

Add syrup

Measure 2 tablespoons of chilled strawberry-basil syrup per glass (about 4 tablespoons total for two large glasses). Pour syrup over the ice in each glass.

Optional spirit

If making alcoholic tonics, add 1 tablespoon (15 ml) of gin or vodka per glass now. Stir gently to combine with the syrup and ice.

Top with tonic water

Slowly pour chilled tonic water over the back of a spoon (or directly) into each glass to fill, about 3/4 to 1 cup per glass depending on glass size. Stir once gently to incorporate syrup and tonic without losing too much carbonation.

Garnish and serve

Garnish each glass with 1–2 basil leaves and a strawberry slice on the rim or floated on top. Serve immediately with a straw or cocktail stirrer.

Scaling and storage

Leftover syrup can be refrigerated in a sealed jar for up to 7 days — use it in other drinks, sodas, or desserts. If serving a crowd, multiply the syrup ingredients accordingly and keep syrup chilled until ready to mix.