Note: Prepare this recipe the day before you want it so it can freeze overnight! I suggest making a full batch of blueberry muffins even though you may only use six – finish the rest for breakfast.
In a small bowl, mix together 2 tablespoons of the milk with the cornstarch and whisk until smooth. Set aside. In another large bowl, whisk together softened cream cheese with salt and cinnamon until smooth.
In a large saucepan, add milk, cream, sugar, vanilla extract and corn syrup, whisking together. Bring to a rolling boil – for me, this was over medium heat. Keep a close eye on the mixture because if it gets too hot, it will boil up and over very quickly. You want it to the point when the milk is bubbling and rolling but now boiling over. Once it comes to that point, boil for 4 minutes. I stirred occasionally here. After 4 minutes, remove from heat and very slowly whisk in the cornstarch mixture. I did it in 3 parts – adding 1/3 of it and whisking at a time. Bring back over heat and bring to a rolling boil again, this time stirring with a spatula while the mixture just thickens slightly – about 1-2 minutes.
Remove from heat and very slowly pour a small amount into the large bowl that has the cream cheese in it, whisking constantly until smooth. Gradually pour the rest of the mixture into the bowl while whisking to combine. Grab another very large bowl and fill it halfway full with cold water, adding a bunch of ice cubes as well. Pour the milk mixture into a one gallon freezer ziplock bag, pushing the air out and sealing it. Place it in the ice bath for 30-45 minutes until cold, adding more ice if needed.
Pour the ice cream mixture into your ice cream maker and churn according to the directions. I used the attachment on my Kitchenaid mixer and churned for exactly 25 minutes. After 20-22 minutes, add a 2-3 crumbled blueberry muffins. Once churned to your desired consistency, place in a freezer-safe container – at this point, I folded in 2-3 more crumbled blueberry muffins using a large spatula. Smooth out the top then place a sheet of plastic wrap over top, pressing right onto the surface. Freeze for at least 8 hours, or overnight.