I moved last November into The Presidio, the old Army base in San Francisco, which is now a National Park as well as a place to live and work. It's a really interesting place to live. But the coolest thing I discovered recently is that the Presidio has blackberries growing all over, including the embankments in front and behind my house. I started snarfing the blackberries as I walked to and from my car. I noticed that a lot of other people snarf the blackberries (meaning that I'm not the first person to notice them!). Indeed, here's background about the two varieties of blackberry bushes found in The Presidio. And here's an article from the SF Bay Guardian about foraging for blackberries in Sea Cliff, which is right next to The Presidio.
The more berries I scarfed the more I thought I should harvest them and make something, like a blackberry pie. I don't cook much, so this was kind of thrilling -- the idea of harvesting free food right outside my house and making it into something good to eat. I found a recipe, which is pretty simple and straightforward. It is particularly simple if you use Pillsbury's pre-made crust, which is as good as most scratch pie crusts I've tasted. I like this recipe because it tells you to cook the pie longer; I used another recipe for my second and third pies, which didn't set as well. That recipe tried to be fancy; it said to bake the pie for 10 minutes at 450 degrees and then reduce the heat and cook for 25 minutes at 350 degrees. The better recipe just said to cook for 45-60 minutes at 450 degrees.
Apparently blackberries thrive in the upper Northwest, where there has been some enthusiastic coverage of how to eat them. This article has a recipe for blackberry cobbler. (Don't know the difference between cobbler and pie.) And this one has a recipe for blackberry jam.