Add the bananas and milk to a blender or food processor and blitz until smooth.
Pour into your Ninja Creami tub. Pop the lid on and freeze for 24 hours.
Remove the tub from the freezer and use the light ice cream function on your Ninja Creami machine. If your ice cream looks chalky or not a nice creamy consistency, use the re-spin function. We used the light ice cream function once and re-spin once.
Make a hole in your ice cream to the bottom of the tub about 2-4cm wide. Add the creamy toffee chunks and use the mix in function to mix. Divide into portions and drizzle with toffee sauce.