In a medium bowl, combine hulled and quartered strawberries, 4 Tbsp sugar and 4 Tbsp liqueur, stir to combine then cover and refrigerate at least 1 hour and up to 2 hours, stirring once or twice.
Just before serving, in a large mixing bowl, combine 1 cup cold heavy cream and ¼ cup powdered sugar, and beat with an electric mixer until stiff peaks form. Using a spatula, fold in ¼ cup sour cream just until well blended.
To serve, stir strawberries then divide between 6 serving glasses or bowls. You can spoon a little syrup over the berries if you like. Spoon cream over strawberries, dividing evenly. Serve right away or chill and enjoy within 2 hours of assembly.
