Whisk the yeast into the hot water and leave for a couple of minutes.
Place flour, salt and maca (if using) into a large bowl. Make a well in the centre and pour in the yeast followed by 1 tbsp of olive oil.
Stir until just combined, then knead on an oiled surface for a good ten minutes or so when the dough should be smooth and elastic. Place back in the bowl, cover and leave to rise for an hour or until doubled in size.
Peel, core and seed the butternut squash, then chop into small cubes. Heat 2 tbsp oil in a medium sized saucepan and fry the squash cubes over moderate heat, stirring occasionally for about 10 minutes, until just soft.
Remove the squash from the pan and set aside. Add the remaining tbsp of olive oil and fry the onion gently for a few minutes. Add the garlic and chilli and fry for another couple of minutes.
Add the tomatoes, herbs and tamari. Cover and allow to simmer for fifteen minutes or so when the sauce should be thick enough not to fall off the pasta, but not too dry. Remove from the heat, add the chocolate, stir and leave to cool.
Heat the oven to 200℃. Cut the dough into four pieces and roll them out as thinly as you can. Place onto oven trays.
Cover the four pizza bases with the tomato sauce to about 1 cm from the edge. Scatter the squash cubes over the top, followed by the tomatoes and then the walnuts. Place the cheese strategically around the pizza then bake for ten minutes or until the crust has browned and the pizza looks done.