Preheat the oven to 400 degrees.Toss cubed squash with 1 tablespoon olive oil and 1 3/4 teaspoons of stevia and spread out a single layer on a sheet pan. Roast for 20 to 30 minutes or until tender and beginning to brown, gently stirring halfway through roasting. Set aside. In a medium pot, heat 2 tablespoons olive oil over medium high heat. Add onion and garlic and saute 5 minutes more. Add broth and 1 cup water and bring to a boil. Reduce to a simmer and cook 10 to 15 minutes or until apples are tender. Stir in roasted squash to combine. Puree soup in batches in a blender until very smooth. If soup is too thick, add addition water until desired consistency is reached. Return to pan and season with 2 3/4 teaspoons of stevia and salt. Divide between bowls and garnish with thinly sliced apple, pepper, and pumpkin seeds.