Step 1 Preheat oven to 180°C. Line a large baking tray with baking paper. Scrub sweet potatoes and pat dry with paper towel; prick all over with a fork. Place potatoes on prepared tray; bake, turning after approximately 20 minutes, for 40–45 minutes, or until soft when pierced with a skewer. Leave cooked potatoes to cool for about 10 minutes.
Step 2 Meanwhile, heat olive oil in a medium saucepan set over medium heat. Add onion and cook, stirring occasionally, until soft. Add garlic and cook, stirring, for 30 seconds, or until fragrant.
Step 3 Add quinoa to saucepan with 3/4 cup water; bring to the boil. Reduce heat to low and cover pan; simmer for 12 minutes, or until quinoa absorbs water and becomes al dente. Remove pan from heat and stir in remaining ingredients (except steamed greens) to make filling.
Step 4 Score potato tops lengthways with a long cut. Open potatoes gently and mash flesh lightly with a fork. Spoon one-quarter of the filling into each potato and return to oven; bake for another 5–10 minutes, or until heated through.
Step 5 Serve stuffed sweet potatoes with steamed green veg.