Line a sheet tray with foil and place the spaghetti squash cut-sides up.
Brush the pieces with 2 tablespoons olive oil (1/2 tablespoon for each piece), then sprinkle them with 1 teaspoon of salt and pepper (1/4 teaspoon for each piece).
Flip the squash so that the cut sides are down, then poke holes into the skins with a fork.
Roast for 35-40 minutes, until tender.
Meanwhile, toast the nuts in a skillet over medium heat until lightly browned. Remove from the skillet.
Heat the remaining tablespoon of olive oil in the skillet over medium heat.
Add the lamb and crumble. Cook until browned.
Add 4 cloves of minced garlic, the cumin, paprika, turmeric, cayenne, and 1/2 teaspoon each of salt and pepper.
Once combined, add the chickpeas and diced tomatoes. Stir to combine.
Add the spinach and stir to wilt into the mixture.
While the lamb mixture simmers, stir together the yogurt, lemon juice, remaining 1/2 teaspoon of salt and pepper, and the remaining garlic clove, grated.
Once the squash is tender, remove from the oven and fluff with a fork.
Fill each half with a quarter of the lamb mixture and top with yogurt.