Preheat oven 375 degrees.

Cut squash in half lengthwise and scoop out seeds. Place on baking sheet lined with parchment paper flesh side down.

Bake 30-35 minutes until squash can easily be pierced with fork. Remove from oven, flip over and allow to cool.

Meanwhile in a medium sauce pan melt butter and olive oil over medium heat. Add onions, garlic, and mushrooms. Cook 6-8 minutes until onion is slightly translucent. Set aside.

In large mixing bowl spoon out squash flesh and mash with potato masher. Add cooked rice, mushroom mixture, thyme, garlic powder, salt & pepper to taste. Mix well.

Shape into equal size burgers and place on baking sheet with clean parchment paper.

Bake in preheated 375 degree oven 20 minutes each side.