Strawberry rhubarb is one of the most common combinations, which is strange because on our farm, rhubarb is ready long before the strawberries! They definitely compliment each other perfectly, but rhubarb is also delicious on it’s own in desserts, chutneys, and even pickled. This tart, with rich brown butter, is delicious and will surely be a hit at potlucks and parties. Don’t be intimidated by the three parts that make this dessert, if you make the crust and streusel topping in advance this comes together in no time.
Start with the crust. Using a food processor, this crust is easy since it is just pressed into the pan and does not need to be rolled out. The crust needs to be chilled ahead of time, and there are a few options. If you make the crust a day in advance just chill it in the refrigerator overnight. Alternately, you can make the crust and streusel about two hours ahead of time, and chill them in the refrigerator. Or, you can do what I did and chill the crust for 20 minutes in the freezer, then make the streusel, and filling. The streusel can also chill in the freezer while the crust bakes.
If you’ve never browned butter before, it’s easy but you need to watch it carefully. Use a light colored pan, so you can see when it turns brown. Melt the butter chunks over medium heat stirring constantly. The butter will foam, that’s the water boiling off. As soon as the butter smells toasty and turns darker, remove from heat and from the pan! It will keep cooking a little when it’s removed from the heat so be careful not to overcook.
Mix together the filling ingredients and then let the rhubarb filling sit for about 15 or 20 minutes until the sugar is dissolved. Stir once or twice to make sure the dry ingredients are thoroughly mixed.
While the rhubarb is sitting and the streusel is chilling, parbake the crust. When the crust is ready, lower the oven heat, and assemble the tart. Bake until the edges are brown and bubbly.
Make the crust. Blend flour, sugar, and salt in processor 5 seconds. Add the chunks of butter, and pulse until coarse. Add egg yolk and 3 tablespoons cream. Blend until moist clumps form, adding more cream if dough is dry. Gather dough into ball. Press enough dough into 10-inch-diameter tart pan to make 1/4-inch-thick crust. Pierce crust all over with fork. Chill overnight or at least 2 hours in the refrigerator or 20 minutes in the freezer.
Make the topping. Cook butter in large skillet over medium heat until golden, stirring often, about 5 minutes. Remove from heat. Mix streusel ingredients together, then add butter gently mixing until just mixed. Cool completely. (Crust and streusel can be made 1 day ahead. Cover separately and chill.)
Preheat oven to 375°F.
Make filling. Toss all ingredients in bowl to blend. Let stand until sugar is dissolved, stirring occasionally, about 15 minutes.
Bake cold crust until golden brown, pressing with back of fork if crust bubbles, about 20 minutes. Remove from oven. Reduce oven temperature to 350°F.
Spoon filling into warm crust. Crumble streusel over. Bake until filling is bubbling and streusel is crisp and brown, about 1 hour – 1 hour + 15 minutes depending on your oven. Cool tart 30 minutes. Serve warm or at room temperature