Finally...Sugar. Here's a pretty old-fashioned recipe that's pretty hard to mess up. Trust me on this point.
You can even substitute the blueberries with other fruits that are in season like: cherries, peaches, apples, raspberries, blackberries, apricots,etc. I wouldn't suggest things like watermelon, cantaloupe, strawberries (although strawberries might work well mixed with other berries or with rubarb...mmmm....must try that next!) I'll even tell you below, other things you can substitute to make this recipe to your liking.
Blueberry Bar Recipe
1 C. White Sugar
1 tsp. baking powder
3 C. All-purpose flour
2 C. cold butter (2 sticks or 8 oz.)
1/4 tsp. Salt
juice of 1 lime or lemon
4 C. blueberries
1/2 C. White Sugar
4 tsp. Cornstarch
Preheat your oven to 375 degrees. Grease your 9 x 13 inch pan. I usually skip this step because I use a glass dish and it never seems to stick. And I'm lazy.
In a medium bowl, wisk together 1 C. Sugar, 3 C. flour, salt, and baking powder. You may substitute up to 1 C. flour with whole wheat flour, ground up oatmeal (or half cup of old-fashioned oatmeal), or other flour of your choosing. I had some left over hazelnut flour and ground up oatmeal so I tossed that in there, hence the brown flour in the picture.
You can even substitute up to half cup with brown sugar which makes the crust really soft and chewy but the crust will also get soggy in this recipe much faster. It just means you have to eat it faster.
Cut the butter into small pieces. The butter should be nice and cold. Ignore the fact that my butter is melting.
Cut it into the flour mixture. You can use a pastry cutter, a fork or butter knives, but I use my hands (because I'm lazy, remember?). If you use your hands, move quickly. You don't want the butter to melt. Just rub the butter into the flour until it looks like sand.
Then add the egg. You really should wisk the egg first then add it to the buttered flour (again, I'm lazy. See, you really can't mess this up).
Mix it up and put it in the fridge to rest and get cold again while you mix the fruit.
Put the fruit into another bowl. It says 4 cups of blueberries. I really have no idea how many cups I put in here but it's a lot of blueberries. If you substitute stone fruit like apples or peaches it comes out to about 1 cup= 1 apple/peach or so. I like a lot of fruit so I add more. See, simple. Add the juice of a lime or lemon. If the fruit you are using is kinda juicy, you can skip this step.
Add 1/2 c. white sugar and cornstarch. If you know the fruit is not sweet, then feel free to add more sugar. I made vanilla sugar so that's the brown specs in the picture. I'll show you how to make that later. Mix it up and grab your crust back out of the fridge.
Put half of the flour/crust mixture into the bottom of your baking dish and firmly press it down.
Add the blueberry mixture on top of that crust.
Then sprinkle the rest of the crust over the top of the blueberries and set in the oven.
Bake for 1 hour or until the top is slightly brown.
IMPORTANT: Let it cool completely before cutting into it. The juices need to firm up and this could take at least 2 hours.
Once cooled, cut and enjoy!