I have been spending quite some time in my kitchen preserving herbs and the last of veggies from my garden. Now I am sharing the way I freeze summer squash.
I wash and cut the heads in half. Then I scooped up the seeds from the middle and placed the halves on a cookie sheet. I put some olive oil on the cut halves and salted them just a bit. Then they were ready to be put in the oven at 400 degrees for about 40 minutes.
After the 40 minutes, I checked if they were soft enough to take out. Depends on your oven, you might check earlier. I took them out and let them cool down. Then I scooped up the flesh an pureed them in the blender.
Muffin pan would be the best to freeze them in smaller portions (by the way, this reminds me of making baby food for my kids - if you are doing that, don't salt the halves and put the pureed mixture in ice cube trays). I let it freeze overnight - don't panic if you forget about them... They will be fine until you actually need the muffin pan ;-) (you might want to cover it though)
Last step was bagging and labeling the squash for storage in the freezer! I can add this to my soups or simply spice it and use it as a side dish (cinnamon and vanilla sugar tastes especially good for kids' snacks - just saying ;-)