Place vegetable stock and quinoa in a saucepan; bring to the boil. Simmer until quinoa is tender, about 15 minutes.
Place Brussels sprouts, carrots, parsnips and red onion on a baking tray; drizzle with 1 teaspoon olive oil.
Roast in the preheated oven until softened, about 10 minutes.
Mix chickpeas with turmeric in a bowl. Heat remaining 1 teaspoon olive oil in a pan over medium heat. Cook and stir chickpeas until browned, about 8 minutes.
Mix tahini, lemon juice and maple syrup in a bowl until well combined. Add hot water, 1 tablespoon at a time, until dressing is thin and smooth.
Divide quinoa, roasted vegetables, chickpeas and mashed avocado between 2 serving bowls. Drizzle 1 tablespoon dressing over each bowl.