My first experience cooking summer squash was when I was 14 years old and obsessed with calories. My mom told me how my grandmother used to make it-cooked way down with onions and a lot of butter- and that it was one of the simplest yet most delicious vegetable dishes. I wasn't a fan of using butter, but used a little cooking spray and topped it afterwards with "buttery spray", which is as artificial as it sounds. Delicious as promised, even made my low-cal way.
Fast forward 10+ years, and a variation on this is still my favorite way to cook summer squash. I still want to keep it on the light side, but now know that leaving a tad bit of bacon grease in my pan will add a ton of flavor without compromising the healthiness of my dish (and no more buttery spray involved!). And you can definitely skip the bacon and use a little bit of some other fat (olive oil, butter, or coconut oil). Sometimes I add a tiny drizzle of truffle oil at the end.
The key to this dish is letting it cook for a bit. The method is sort of a combination of sauteing and stewing. There is plenty of moisture as the squash breaks down, but the heat is higher than a traditional stewing process and there is more browning. The heat is low enough, though, that some moisture does build up and you don't have to stir as often as during traditional sautes.
The end result should have some nice golden color and also reduce down to almost create a mush (I was actually a little impatient this time around... my squash wasn't quite mush enough! :-/). This is what really lets the natural sweetness shine and eliminates the need for additional seasoning. The bacon adds a little salt, so you won't need to add extra unless you don't use bacon.
4-5 strips bacon
1 medium onion (I used a sweet onion), sliced or diced
3 small summer squash, sliced thinly
1 head garlic, peeled and cloves cut into slices
4 green onions
Start by frying the bacon in a large frying pan over medium/medium-high heat. Once the bacon is fully cooked (the crispier you make it, the more you render the fat out), remove the strips from the pan and drain over paper towel. Discard all but 1-2 teaspoons of the bacon grease. There should be a very thin coating on the bottom of the pan.
Add the onion, squash, garlic, and jalapeno to the pan. Saute/stew, stirring only every couple minutes, until the squash breaks down and all vegetables have a lovely golden color. If things are sticking too much, reduce heat a little. This should take at least 20-25 minutes and you can keep cooking it beyond that to deepen the flavor. You can baby it if you want and stir more often, but I find that stirring less often works perfectly well and that way you can wash some dishes or prep other parts of dinner at the same time. Once you've achieved a suitably mushy state, add the green onions and crumble in the reserved bacon strips.
And enjoy! This would be a perfect accompaniment to some salmon or barbecued chicken.