Preheat oven to 200C/400F and lightly spray with oil a baking tray.
In a bowl, mix together your leftover mashed sweet potatoes ⅓ of panko breadcrumbs and grated garlic. Season well with salt and pepper and mix until combined.
In another bowl mix together the ricotta with fresh herbs, lime juice and zest. Add finely chopped roasted bell pepper and season well with salt and pepper to taste.
Whisk the white eggs in one bowl and place the remaining panko breadcrumbs in another bowl.
Take 1 heaping tablespoon of mashed sweet potatoes, shape into a slightly flattened ball and add into the center a teaspoon of ricotta mixture. Close and shape it into a croquette. Repeat the process with remaining ingredients.
Place your croquettes into a tray and freeze for 10 mins, or until hard enough to handle.
Dive your croquettes into the whisked eggs then coat on all sides with panko breadcrumbs. Place on the greased baking sheet. Repeat the process for each croquette.
Bake for about 15 mins or until the tops are crispy and golden brown and the center is hot.
Serve them straight away from the oven or at room temperature.