Bring mixture to a gentle simmer, mashing the berries with a spoon or a potato masher to release juices. Simmer for 6–8 minutes until the sugar is dissolved and the mixture thickens slightly.

Remove from heat, stir in 1 tablespoon fresh lemon juice, and let the syrup cool for 10–15 minutes to steep and concentrate flavor.

Strain the syrup through a fine mesh sieve into a bowl or jar, pressing on solids to extract as much liquid as possible. Discard solids. Cool to room temperature, then refrigerate until chilled. Makes about 3/4 cup syrup.

Assemble the Mocktail

Prepare glass

Chill a large wine glass or highball glass if possible. Fill the glass with about 1 cup of ice cubes.

Add 2 tablespoons non-alcoholic citrus rum, 1 tablespoon elderflower cordial, and 1 tablespoon fresh lime juice directly over the ice.

Measure and add 2 tablespoons (about 1 oz) of the prepared blueberry syrup into the glass. Gently stir once to combine the base ingredients.

Slowly top with 4 oz chilled non-alcoholic cava (or sparkling white grape juice). If you prefer a lighter spritz, add 1 oz chilled club soda on top instead of some cava.

Give the drink a gentle stir twice to incorporate the bubbles without flattening them.

Garnish with 6–8 fresh blueberries threaded on a cocktail pick or floated on top, a lime wheel or wedge on the rim, and an optional mint sprig for aroma.

Serve immediately with a straw or stirring stick. If making multiple servings, scale ingredients and assemble in a pitcher (add sparkling elements just before serving).