Add sweet potatoes to a saucepan of boiling water and simmer for 10 minutes until tender.
Drain sweet potatoes and add them to a large bowl.
Mash them and season them well with salt and pepper.
Meanwhile, preheat the oven to 200 degrees Celsius.
Stir in the grated parmesan and garlic to the sweet potato mash and combine well.
Pour the panko breadcrumbs on to a plate.
Line a baking tray with greaseproof paper and spray well with 1 kcal spray.
Form the sweet potato mash into croquette shapes and roll in panko breadcrumbs until well coated.
Add the croquette to the lined tray and repeat with the rest of the sweet potato mash. You should have enough for about 15 croquettes.
Spray the croquettes well with 1 kcal spray and bake for 15-20 minutes until crispy.
You can switch to the grill for the last 5 minutes if you need to crisp them up.
Garnish with parsley and serve.