Cut your squash in half from stem to base, scoop out all the seeds.
Place the trivet that came with your Instant Pot on the bottom of the Instant Pot.
Add 1 cup of water to the pressure cooker.
Put in your spaghetti squash facing each other, but with space between them. If your squash is too big to fit, cut it into quarters.
Secure the lid on the Instant Pot, set it to "sealing". Set to 8 minutes on high pressure.
Meanwhile, saute ½ onion and 3 cloves of garlic in 1 tablespoon of olive oil until translucent, about 4 minutes.
Add 3 cups of marinara sauce and 1 teaspoon of oregano to the onion and garlic mixture and heat it up.
When the timer of the Instant Pot beeps, signaling that it is done, switch to "venting" to release steam. Be sure to use a long-handled spoon or oven mitt so you don't get burned from the steam as it spurts out!
When the pressure is fully released and the pressure indicator has dropped, remove the lid.
Then, use tongs to move the spaghetti squash to a cutting board.
Your squash should be tender when pierced with a fork.
Using a fork, pull up threads of "spaghetti", use a spoon to transfer the "spaghetti" to the pot with the marinara sauce, or you can just place "spaghetti" on a plate and serve the heated marinara sauce on top
Alternatively, if mixing the "spaghetti" noodles into the marina sauce, after it is mixed, spoon the marinara mixture back into the squash "boat".
If you like, you can put mozzarella cheese or parmesan cheese on top and broil in the oven for a couple of minutes.
However, we like to add cottage cheese to ours and simply dig in! Yum!