Preheat your oven to 400°F (200°C) and line a baking sheet for easy cleanup. Wash the spaghetti squash thoroughly and, for easier handling, carefully cut off both the stem and the base. I find it easiest to cut the squash into 2-inch thick slices across its width; this not only speeds up cooking but also makes seed removal simpler and allows for more even roasting. Scoop out and discard all the seeds from each slice. Arrange the squash slices on the prepared baking sheet and drizzle them with the olive oil, ensuring each piece is lightly coated before seasoning.

Now, sprinkle the cinnamon over the olive oil-coated spaghetti squash slices; this adds a lovely, subtle sweetness that babies often enjoy. Bake the squash for approximately 20-22 minutes, or until it's very tender when pierced with a fork. The exact time will depend on the thickness of your slices and your oven, so keep an eye on it. Once done, remove it from the oven and allow it to cool slightly before handling.

Once the spaghetti squash is cool enough to handle, use a fork to gently scrape and loosen the strands from the skin – they should come away easily if cooked correctly. In a small bowl, combine these warm spaghetti squash strands with the marinara sauce and a sprinkle of shredded cheese. Stir everything together until well combined and the cheese is slightly melted. I like to taste a small bit here to ensure the temperature is appropriate and the flavors are balanced before serving it to a baby, ensuring it's not too hot.