In a bowl, combine the strawberries and granulated sugar; toss to coat and let stand until the berries release juices, 10–15 minutes.
Scrape the macerated mixture with its juices into a blender, add the whole milk and vanilla ice cream, and blend on medium-high until smooth and thick but pourable, 20–30 seconds, stopping to scrape down the sides as needed.
Adjust consistency if desired: blend in 1–2 tablespoons more milk to thin or a small scoop more ice cream to thicken; pour into two chilled glasses and serve immediately.