Step 1Preheat the oven to 200°C. Line a large baking tray with baking paper. Prick the sweet potatoes all over with a sharp knife. Place in a microwave-safe container and microwave on high for 10 minutes, or until soft.
Step 2When cool enough to handle, cut a long opening into the top of each potato, being careful to leave ends uncut. Using a tea towel to hold potato, scoop out centres, leaving 1cm-thick shells.
Step 3Place potato flesh in a bowl and season with cracked black pepper. Mash with a fork. Stir in the shallots, chilli (if using), beans and half of the coriander. Spoon the filling back into the potato shells. Sprinkle the shells with the grated cheese.
Step 4Place potatoes on prepared tray. Bake for 10 minutes, or until heated through. Sprinkle with remaining coriander and serve.