Try mixing in the apple pieces into the mug cake before you cook it. You could also make it more decadent by adding some white chocolate chips!
Mix all your dry ingredients together in a big mug.
Add the greek yogurt and apple puree and stir through until thoroughly mixed.
Stir the nut butter through as well.
Carefully pour and mix the milk into the batter. It has a tendency to slosh a bit, so mix it slowly, letting the milk fall into the mixture before you mix more vigorously.
Microwave the batter for 1 minute and 45 seconds (850W).
Add the apple pieces from the toffee apple punnet to the top of the mug cake.
Pour over the toffee sauce. You could also sprinkle some more chia seeds, or add any other toppings you fancy.