Muddle the blueberries - In a cocktail shaker, use a muddler to mash the blueberries until they release their juices and become somewhat crushed. - Make sure to not over-muddle the blueberries, as this can cause them to become bitter. You want to release their flavor, not pulverize them.

Add the other ingredients - Add the vodka, lemon juice, and ice to the cocktail shaker. Close the shaker and shake vigorously for 10-15 seconds. - Use fresh lemon juice instead of bottled for the best flavor. And make sure to fill the shaker with plenty of ice to get the cocktail nice and cold.

Strain and pour - Strain the cocktail through a fine-mesh strainer into a large measuring cup or pitcher, pressing on the solids to extract as much liquid as possible. Discard the solids. Pour the cocktail into martini or wine glasses, filling them about 2/3 full. - If you don't have a fine-mesh strainer, you can use a regular strainer or skip this step, but the cocktail will be slightly pulpy. And don't fill the glasses too full, as you want to leave enough room for the sparkling wine.

Top with sparkling wine - Top each glass of the cocktail with sparkling wine. You can do this by pouring the sparkling wine directly into the glasses, or by pouring it into the measuring cup or pitcher with the cocktail and stirring gently to combine. Stir gently to combine. - When pouring the sparkling wine, tilt the glass at a 45-degree angle and pour slowly down the side, then slowly straighten the glass as you pour to create a frothy head of bubbles. And don't stir too vigorously, as you don't want to lose all the carbonation in the sparkling wine.

Garnish and serve - Garnish each glass with a lemon twist or wedge and a few fresh blueberries. Serve immediately and enjoy! - To make a lemon twist, use a vegetable peeler or a knife to cut a long, thin strip of lemon peel. Twist it over the glass to release the oils, then curl it around a pencil or your finger to create a spiral.