Preheat the oven to 180°C (350°F). Line two baking trays with plastic-free baking parchment. Spread the sweet potato evenly on one of the prepared trays, sprinkle with garlic salt and drizzle with 1 teaspoon of the olive oil. Bake for 20-25 minutes, or until the sweet potato is golden brown. Spread the tomatoes on the other prepared tray, season with salt and pepper and drizzle with 1 teaspoon of the olive oil. Bake for 8-10 minutes, or until softened.
Place the eggs in a small saucepan of boiling water for 5 minutes, or until soft boiled. Refresh in iced water, peel, halve and set aside.
Meanwhile, heat the remaining olive oil in a medium frying pan over a medium heat. Add the garlic and cook for 1 minute, or until fragrant. Add the mushrooms and cook until just browned. Season with salt and pepper.
Place the pumpkin seeds in a small frying pan over a medium–high heat and dry-fry for 2–3 minutes, or until slightly golden, tossing constantly.
To assemble the bowl, layer the quinoa, sweet potato, tomatoes, mushrooms, eggs, avocado, toasted seeds and pickled red onions in a serving bowl. Season with salt and pepper and squeeze with fresh lemon juice to serve.