Preheat oven to 180 degrees celsius.
Have 4 x 10cm shortcrust pastry tart cases ready for use that has been baked blind.
Heat oil in a saucepan over medium heat. Add the spring onions and fry for 8 - 10 minutes until soft and lightly browned.
Add the diced bacon and cook for a further 10 minutes until lightly browned.
Add the grated beetroot, thyme, balsamic vinegar, nutmeg, salt and black pepper to taste. Allow the mixture to cook for a further 10 - 15 minutes or until the moisture has evaporated.
Remove from the heat and set mixture aside to cool.
Once cooled, add in the grated mozzarella cheese and stir until well distributed.
Divide the beetroot mixture between the pastry cases that have been baked blind.
Whisk together the fresh cream, egg, egg yolk and baking powder. Pour the custard mix, in equal proportions, over the beetroot mixture.
Bake at 180 degrees celsius for 25 - 30 minutes or until the custard is set and lightly browned.
Remove from oven and allow to stand for 10 min.