Combine the sliced strawberries in a medium bowl with the sugar and vodka. Stir until the sugar begins to dissolve. Cover and let stand at room temperature for 1 hour, stirring occasionally. Transfer the mixture to the bowl of a blender or food processor and add the sour cream, heavy cream and lemon juice. Pulse briefly until almost smooth but still slightly chunky. Chill in the refrigerator for 1 hour. Freeze in an ice cream maker according to the manufacturer’s instructions.