Prick the sweet potatoes all over with a fork and put on a microwave-safe plate. Microwave on high for 5-6 mins until tender – a sharp knife inserted into the thickest part should go in easily.

Melt the butter in a large microwave-safe bowl, then stir in the garlic and onion. Loosely cover and cook on high for 1 min until softened. Stir in the black beans, chopped tomatoes, chilli powder, cumin and sweetcorn.

Cover again and microwave on high for 5 mins until bubbling and hot, then season and spoon this over the sweet potatoes. Top with soured cream, guacamole, coriander leaves and some black pepper, and serve with lime wedges for squeezing over, if you like.