Preheat the oven to 400 degrees F. Chop the tip and tail off of the acorn squashes, slice in half, and scoop out the insides. Drizzle the flesh with a small amount of oil and sprinkle with sea salt. Place squash cut-side down on a large baking sheet and bake 50 to 60 minutes, until very tender when poked with a fork.
While the acorn squash is roasting, prepare the ground beef filling. Add 1 Tablespoon avocado oil to a large skillet and heat to medium. Add the onion and saute, stirring occasionally, until onion is very soft, about 5 to 8 minutes.
Add the brussels sprouts and garlic, cover, and cook 4 minutes, stirring occasionally.
Scoot the vegetables off to one side of the skillet and add the ground beef. Allow it to brown 2 to 3 minutes, then mix it into the rest of the skillet. Add the remaining ingredients (oregano through kale), cover, and cook until kale has wilted, about 5 minutes.
Place acorn squash halves on plates and stuff with desired amount of the beef stuffing mixture. Serve with your favorite side dish and enjoy.
*omit the onion, brussels sprouts, and garlic to make Low-FODMAP - you can replace them with other vegetables, like carrot and broccoli, if you'd like.