Hull and slice the strawberries into 1/4-inch rounds, then place them in a bowl with the sugar and vanilla extract. Stir gently to combine, allowing the sugar to draw out the strawberries' natural juices and create a light syrup. Let this sit for 15-20 minutes while you gather your serving glasses and other components—this partial maceration will sweeten the berries without requiring a full 30-minute wait, and you'll have more control over the texture.
Divide the strawberries and their syrup evenly between two serving glasses, using about half the mixture on the bottom of each glass. Spoon half of the yogurt over the strawberry layer in each glass, then scatter half of the blueberries on top. I like to reserve the prettiest blueberries for the top layer so they catch the eye when served. Next, divide the granola between the two glasses, pressing it gently into the yogurt layer so it holds its crunch longer. Top each parfait with the remaining strawberries, yogurt, and blueberries, creating a beautiful striped effect.
Top each parfait with a fresh mint sprig for a pop of color and subtle freshness. Serve immediately while the granola is still crunchy and the yogurt is cold—this is the ideal moment for texture contrast between the creamy yogurt, juicy fruit, and crispy granola.