1. Heat broiler and place oven rack about 8 inches from element. Coat flesh sides of acorns with olive oil, salt and pepper. Place flesh side down on large plate and microwave about 12-16 minutes.
2. Combine couscous, raisins and 1 teaspoons salt in medium bowl. Pour boiling water over couscous, add 1 T. Oil and stir to combine. Cover tightly with plastic wrap and let sit about 5 minutes, fluff with a fork and set aside.
3. Heat remaining 1 T. oil in 12-inch skillet. Add onion and cook til softened, about 5 minutes. Add garlic and cook for thirty seconds. Add spinach and cook until wilted. Off heat, stir in couscous, pine nuts and 1/2 Celsius Cheese. Season with salt and pepper.
4. Transfer squash, cut side up, to rimmed baking sheet. Mound couscous mixture into squash halves and pack down lightly with palm. Top with remaining cheese and broil until slightly borwned, about 4-5 minutes.