Peel the onions and finely chop them. Peel the garlic cloves and crush or finely chop them. Halve the chilli, scraping out the membrane and seeds for less heat, and finely chop it. Separate the coriander stalks and leaves (save the leaves for later in the recipe). Finely chop the stalks. Roughly chop the tomatoes.
Top and tail the squash, then peel it. Slice in half lengthways and scoop out the seeds with a spoon. Coarsely grate the flesh (if you have a food procesor, whizz it through the grater attachment to make this extra easy). Drain and rinse the beans.
Pour 1 tbsp oil into a large pan over a medium heat. Add the onions, garlic, chilli, coriander stalks and 1 tbsp each smoked paprika and ground cumin along with a good pinch of salt and pepper. Fry for 5 mins, stirring occasionally, till slightly softened.
Add the beans, squash and tomatoes. Cook for a further 5 mins.
Stir in 1 tbsp cocoa powder and the lentils. Crumble in the stock cube. Pour in 1 ltr boiling water. Bring to a simmer, then reduce the heat and cook gently for 40 mins, stirring occasionally.
Taste the chilli and add more salt and pepper if needed. Ladle into bowls and scatter over the coriander leaves.