In a large bowl, whisk together 1 1/2 cups of milk and 1 1/4 cups sugar until the sugar is dissolved. Add 3 cups of heavy cream and 1 1/2 tbsp of vanilla extract and whisk to combine.
Pour into the base of your ice cream maker and let churn for 25-30 minutes, until soft serve consistency.
Once the ice cream is ready scoop it into a large bowl and add 1 1/2 - 2 cups of the blueberry compote (reserving the rest for a sauce), gently fold in the blueberries. DO NOT OVER STIR.
Break up the oat crumble mixture into small pieces and add it to the ice cream, fold it in gently.
Pour into a freezer proof pan (I used my 9"x5" bread loaf pan), and place in the freezer for 3-4 hours or until desired consistency.
Serve with the extra blueberry sauce on top if desired.