Step 1

Preheat oven to 375°. Slice squash lengthwise and scoop out seeds. Place squash, cut side down, in a baking dish. Add water and cover tightly with foil. Bake until easily pierced with a fork, 20-30 minutes. Meanwhile, in a cast-iron or other heavy large skillet, cook beef over medium heat, crumbling meat, until no longer pink; drain. Add onion, green pepper, herbs and seasonings; cook and stir until onion is tender, 5-7 minutes. Stir in tomato puree. Cover and cook over low heat, stirring occasionally.

Step 2

Scoop out squash, separating the strands with a fork. Just before serving, stir 1/2 cup Parmesan cheese into meat sauce. Serve sauce over spaghetti squash with remaining 1/2 cup Parmesan cheese.