Fry the bacon in a frying pan over a high heat for around 10 minutes, until brown and crispy. Remove from the pan and place on a kitchen towel to remove excess fat.
Pour the remaining fat out of the frying pan (you only need a thin sheen on the bottom) and dice the onions. Cook the onions in the same pan you cooked the bacon for around 10 minutes, until soft and just starting to turn golden. Place the onions in the Crock Pot.
Chop the bacon into small strips and place in the Crock Pot.
Peel, core and chop the apples into small chunks - place in the Crock Pot.
Wash the potato (I leave the skin on), chop into small chunks and place in the Crock Pot along with the grated cheese.
Pour over the vegetable stock and apple juice and stir.
Leave to cook on high for around 4 hours or on low for around 6, until all the ingredients are soft.
Pour the soup into a flat-bottomed container and use a hand-held blender to process until all the lumps have been ground up.
Divide between 4 or 6 bowls and serve.