Preheat oven to 425°F. Then slice the spaghetti-squash lengthwise & scoop the seeds out. Put the 2 halves face-down onto a baking-sheet and bake for half an hour.
While the squash is cooking, then prepare sausage. Heat a large-pan over moderate heat & add from the sausage.
Split it into pieces with a spatula and cook, stirring occasionally till cooked through and browned for 8minutes. Remove from pan and put aside. Reserve at least 1 tablespoon of fat from the pan to the sauce you will create after.
Remove squash from oven after 30minutes then put aside to cool. Keep the oven at 425°F.
While the skillet is cooling, prepare the creamy-garlic-sauce. Whisk together coconut-milk along with arrowroot-flour in a jar or bowl and put aside.
Heat the same-pan that you cooked the sausage in over moderate heat. Once hot, add mushrooms and cook till they start to soften, about two minutes. Then add minced garlic and combine well with the mushrooms, about a few minutes till aromatic.
Then whisk the coconut-milk mixture and add to pan, stirring constantly for two minutes. The sauce will bubble & thicken, keep stirring to avoid burning. After two minutes turn heat off and stir in pepper and salt.
Now, put it all together. Using a fork, scrape-out the "spaghetti squash noodles" to a medium casserole-dish. Then add the cooked broccoli, sausage and creamy garlic sauce. Mix everything together nicely.
Put back into the oven to bake for 15minutes. Remove and serve.