Place rack in centre of oven. Preheat oven to 200°C (400°F). Line a baking sheet with parchment paper.

For the squash: Cut in two lengthwise. Remove seeds with a spoon. Oil, salt and pepper the squash, then place cut side down on the baking sheet.

For the stuffing: Cook the quinoa for 12 to 15 minutes in a saucepan of boiling salted water. Rinse under cold water and drain well. Set aside. In a frying pan, brown the onion and garlic in oil. Add the quinoa, pepper and raisins. Reheat over medium heat, stirring frequently. Add 125 ml (1/2 cup) of Cheddar and coriander, if desired. Season to taste.

Bake the squash in the oven for 40 to 45 minutes, or until tender. Fill the squash with stuffing. Sprinkle on the remainder of the cheese. Bake in the oven for about 10 minutes, or until the cheese has melted and the squash is piping hot.