Cut ends off squash & cut in half, lengthwise. Scoop seeds out with a spoon & throw away. Place squash in a microwave-safe dish flesh-side up. Microwave 15 minutes, or until tender. Let cool. Score squash with a knife making small squares, without breaking skin. Scoop squash out & set aside.
In a large saucepan add oil & heat over medium. Sauté mushrooms, onion & pepper mix & garlic powder 3-4 minutes, or until vegetables are tender, stirring occasionally.
Add squash. Cook 2-3 minutes, or until squash is golden brown on edges.
Add broth, oregano & pepper. Increase heat to medium-high & bring to a simmer, stirring occasionally.
Stir in lentils. Cover & simmer 30-35 minutes, or until lentils are tender, stirring occasionally.
Add rice. Cover & simmer 10 minutes, or until rice is tender.