Preheat oven to 425 degrees, and prepare a baking sheet covered with foil or silpats. Cut spaghetti squash in half. We cut ours into bowl shapes, but they could be cut lengthwise into boat shapes if desired.
Place into oven for approximately 40 minutes, but keep an eye on them. One of our squashes was smaller than the other and needed to be pulled about 8 minutes before the other. You will know it is ready when the outside just starts to have some give.
While your squash is baking, sautée the garlic in the butter and oil over medium heat until it starts to soften, but don't let it burn! Once the garlic has softened, add the spinach, and sautée until it just begins to wilt. Do not let the spinach cook down to nothing. You still want it to have body.
When your squash has finished cooking, let it cool slightly, and start pulling the insides out into spaghetti-like strands with a fork, and placing them into a large mixing bowl, discarding any seeds. You can really scrape the sides of the squash down and get quite a bit of squash out if you try!
While the squash is still warm, add the cream cheese, milk, and cheese and mix until it is fully and uniformly melted. Add the artichoke hearts.
Taste the mixture. Add salt, pepper, cayenne, and lemon juice as needed. I found that while the artichoke hearts and cheese added quite a bit of salt, it still needed a good pinch, a good bit of pepper and cayenne, and probably about a teaspoon of lemon juice for brightness.
You could serve it in a bowl at this point, or scoop it back into the squash shells, top with some extra cheese and broil for a minute to give it a little color.
