Pre-heat the oven to 225℃ (437℉). Lightly grease a skillet or baking dish - my skillet is 26cm (10").
Peel and chop the apples into fairly small chunks. Set to one side.
Add the sugar, butter, and milk to a saucepan and bring to the boil over a medium heat. Cook for a further 1-2 minutes, until the mixture thickens a little.
Remove from the heat and stir in the cinnamon.
Add the apples and return to the heat to cook for about five minutes, just until the apples start to soften.
When ready, remove from heat, and gently stir in the blueberries, only until they are fairly evenly distributed (too much mixing with burst the blueberries).
Pour into the prepared skilled or dish and evenly sprinkle over the crumble mixture.
Bake for 15 minutes until the fruit juices have bubbled up around the edges, and the crumble is nice and golden.
Allow to cool for a short while (so it is not burning hot when you eat it), and before serving, top with vanilla ice-cream. Enjoy!