Slice the squash in half lengthwise and remove the seeds. Coat with olive oil, sprinkle on some salt, pepper, and thyme and place in a preheated oven (190°C) for 40 minutes.
Cook the quinoa. In the meantime, cut the mushrooms into slices and the chanterelles into quarters. Chop the garlic and finely dice the onion. Fry the mushrooms, chanterelles, onion, and garlic together.
Remove the squash from the oven after 40 minutes. Spoon out the flesh so that the rind makes a sort of boat. Mix the flesh and quinoa filling.
Distribute the quinoa filling equally between the two halves of squash. Garnish with basil.