Preheat the oven to 350°F / 180°C. Wash the outside of the squash and using a sharp knife, carefully cut in half lengthways (if it's too difficult to cut, you can pierce a few holes and cook in the microwave for 1-2 minutes to slightly soften).
Using a spoon, scoop out the seeds and any stringy parts.
Place the squash halves on a baking sheet lined with parchment paper, cut side up. Drizzle with 1 tablespoon of olive oil, season with salt and pepper, and paprika, then rub it over the insides of the squash.
Turn the halves over and rub the outsides with any excess oil on your hands. Use a fork or sharp knife to poke a few holes on the outside of the squash. Bake for 30-35 minutes until they're fork tender.
In the meantime, cook the quinoa in a small pot with 1 cup of water. Once water has absorbed, place the lid on and steam for 5 minutes then fluff with a fork.
In a skillet, saute the onion with 1 tablespoon of olive oil over medium-heat. Once translucent, add the garlic and chopped spinach and saute together.
Once wilted, add 1/2 tablespoon of olive oil, lentils, cooked quinoa, cumin, and season with salt and pepper. Stir together and cook for 2-3 minutes then add the mixture to a large bowl to cool slightly.
Roughly chop the almonds and add them to the bowl with the cranberries. Crumble in the feta cheese, then mix to combine - taste for seasoning and add salt and pepper if needed.
When the squash is fork tender, gently flip them over. Using a spoon, scoop out some of the flesh from the narrow ends of the squash and evenly distribute it to where the seeds were removed. Gently press the filling down so you have an even level base for stuffing.
Stuff the halves with the mixture (you may have a small amount of the mixture leftover depending on the size of your squash). Bake for 5 minutes to warm up the filling and it's ready to serve with chopped fresh herbs for garnish.