This. This right here is proof that this is the best tart I’ve ever had. Mostly because it contains my two favorite ingredients: rhubarb and blackberries. This is best made with fresh berries. Frozen is just not the same! Summer is the best time to experiment with berry recipes because I can go to any number of farms and pick what I want and not pay a fortune.
When I was a kid, my mom had a garden and one of the weirdest things she grew was rhubarb. Of course, I only thought it was weird until I ate it. I think the first time I had it was in a strawberry rhubarb pie. It was out of this world. And I wasn’t a big berry fan when I was a kid. I’ve since converted.
There are so many wonderful flavor pairings with rhubarb. The go-to pairing is strawberry with rhubarb. And while that is in no way inadequate, I really wanted to amp up the flavor of the rhubarb. Enter: blackberries.
You really must go make this recipe before the summer is over and fresh berries aren’t available.
And it may seem like a lot of rhubarb, you really do need this much to fill the pie pan. I mean, who wants a pie without enough filling?
Here’s the finished pie/tart, whatever you want to call it. To top it off there’s a wonderful crumbly topping sprinkled over the filling.
- 6 1/4 ounces flour
- 1/4 teaspoon kosher salt
- 1 stick, cold, unsalted butter
- 1/4 to 1/3 cup ice water
- 6–8 stalks rhubarb, diced
- 6 ounces blackberries, cut in half
- 3/4 cup sugar
- 1 tablespoon King Arthur Flour ClearJel
- 1/2 cup cold butter, grated
- 3 1/2 ounces sugar
- 4 ounces flour
- 4 tablespoons oats
- 1/2 cup walnuts or pecans, toasted, roughly chopped
To make the tart:
- Place 1 stick of unsalted butter in the freezer for 5-8 minutes. In a medium bowl mix flour and salt. Take butter out of freezer and grate, adding it to the flour mixture. You can also cut the butter into chunks and place in freezer in a shallow bowl for 5 or so minutes.* Use a pastry blender if you choose to use the chunks. Toss the flour and butter mixture with a fork. Slowly drizzle 4 tablespoons of ice cold water into the mixture. The dough will start to come together. Slowly add more water until, when squeezed, holds together in your hands. Gather into a ball, shape into a flat disc, wrap in plastic wrap and refrigerate for at least 30 minutes.
- Preheat oven to 375.
- In a large mixing bowl mix together rhubarb and blackberries. Combine sugar and ClearJel in a small bowl before mixing it into the filling. Let sit while preparing topping and crust.
- In another bowl blend butter, sugar, flour, oats and walnuts until pea sized crumbles form.
- Roll out pastry between two pieces of parchment lightly dusted with flour. Remove top piece of parchment, wrap the crust around a rolling and then unroll it over the tart pan. Run rolling pin over top of tart to remove excess dough. Prick the bottom of the tart with a fork a few times to prevent bubbles from forming. Refrigerate at least 30 minutes prior to filling and baking.
- Fill tart with berry and rhubarb mixture. Sprinkle crumble on top. Place tart pan on rimmed baking sheet. Bake in a 375 oven for 15 minutes, then reduce temperature to 350 and continue baking for 40-45 minutes more Remove from oven and cool completely on wire rack.
*It makes it easier to incorporate cold butter and keeps it from softening too much before baking. Cold butter ensures a flaky and flavorful crust. When the hot air hits the cold butter, water in the butter evaporates quickly, allowing for that amazing, flaky crust.