Preheat oven to 180°C and line a baking tray with baking paper.
Place the sweet potatoes onto the tray, drizzle with olive oil - reserving 1/2 tablespoon - and season well. Bake in the oven for 40 minute, or until softened.
Remove sweet potatoes from the oven and scoop out the sweet potato flesh into a bowl, leaving the skin to form a shell.
Heat remaining oil in a frypan and add onion, garlic and chilli. Sauté for 2-3 minutes before adding capsicum, black beans and paprika. Cook for an additional 4 minutes, adding the spinach for the last minute.
Add the bean mixture to the sweet potato flesh and roughly mash together, seasoning as required.
Place the avocado and juice of 1/2 lemon into a bowl and roughly mash. Season well.
In another bowl add the yoghurt, lemon zest and remaining lemon juice and mix until a smooth consistency is formed.
Spoon the sweet potato and bean mixture back into each sweet potato shell and serve topped with avocado, lemon yoghurt and coriander.
Note: The kids liked theirs topped with cheese. I added the cheese after spooning the sweet potato mixture into the shells and I then returned it to the oven for 5 minutes to melt the cheese! They topped them with sour cream!