In a small saucepan, combine raspberries, sugar, and water.
Bring to a low simmer over medium heat, stirring occasionally, until sugar is dissolved and berries begin to break down (about 5–7 minutes).
Remove from heat and let it cool slightly.
Strain through a fine mesh sieve into a jar, pressing gently to extract all the liquid.
Chill until cold. (You can make this up to a week ahead and store it in the fridge.)
Add 1 oz raspberry simple syrup to a champagne flute or coupe glass.
Add ½ oz lemon juice, if using.
Slowly top with 4 oz chilled prosecco — pour gently to avoid overflow.
Garnish with a few fresh raspberries dropped in or a twist of lemon peel on the rim.
Notes
Erren’s Top Tips
Chill both the syrup and the prosecco before assembling for the best bubbles
Pour the prosecco slowly down the side of the glass to prevent overflow
Taste the syrup first; raspberry sweetness can vary, so adjust to taste
For parties, keep syrup and prosecco separate and let guests assemble
Variations & Add-Ins
Add a splash of elderflower liqueur for floral notes
Swap lemon juice for orange peel for a softer citrus aroma
Top with a few crushed frozen raspberries for a slushy-style finish
Turn it into a mocktail using sparkling water or non-alcoholic prosecco
Storage & Make-Ahead
The raspberry simple syrup can be stored in an airtight container in the refrigerator for up to one week. Assemble cocktails just before serving to maintain carbonation.