Strawberry Rhubarb Cake

Preheat the oven to a medium-high temperature of 350 degrees F (175 degrees C).

Make the filling by combining rhubarb, strawberries, sugar, lemon juice, and 1 tablespoon of water in a large saucepan. Place the saucepan over medium-low heat, cover it with a lid, and stir occasionally until the mixture starts to bubble, approximately 5 minutes. Reduce the heat to a low setting.

In a separate small bowl, whisk together the remaining 2 tablespoons of water and cornstarch until smooth. Add this mixture to the saucepan with the fruit filling and continue cooking until it thickens, around 2 minutes. Remove from heat and let cool.

Prepare the pie pan by spraying it with nonstick cooking spray and placing it on a baking sheet. Set it aside for later use.

Make the batter by beating together butter and sugar with an electric mixer in a large bowl until it becomes light and fluffy. Add yogurt, egg, and vanilla to the bowl and mix until well combined. Gradually add flour, baking powder, baking soda, and salt; mix just enough to achieve a combined batter.

Spread two-thirds of the batter into the prepared pie pan. Pour the filling over the batter, followed by a layer of small mounds made from one-third of the remaining batter on top of the filling.

Make the topping by combining flour, brown sugar, and butter in a small bowl. Use a fork, pastry blender, or your hands to mix the ingredients until they resemble coarse crumbs. Sprinkle this topping evenly over the top of the batter and filling.

Bake the pie in the preheated oven for approximately 35 minutes, or until the topping is nicely browned.