1. In a mixing bowl, combine heavy cream, whole milk, sugar, and vanilla extract. Stir until sugar is dissolved.
2. Pour the mixture into an ice cream maker and churn according to the manufacturer's instructions.
3. While the ice cream is churning, prepare the blueberry sauce. In a saucepan, combine blueberries, sugar, and lemon juice. Cook over medium heat until the blueberries break down and the sauce thickens. Let it cool.
4. For the crumble topping, preheat the oven to 350°F (175°C). In a bowl, mix flour, brown sugar, and cold butter until crumbly. Spread on a baking sheet and bake for 15 minutes or until golden brown. Let it cool.
5. Once the ice cream is churned, layer it in a container with the blueberry sauce and crumble topping. Freeze for at least 4 hours before serving.