Preparation

• In a saucepan over medium heat, combine chopped rhubarb, ¼ cup sugar, and water. Cook until tender and sugar dissolves, about 5 minutes. Remove from heat, stir in strawberries, and let cool. Strain excess liquid.
• Preheat oven to 350°F (175°C). Grease and flour an 8×8-inch baking dish.
• In a large bowl, whisk together flour, salt, and remaining ½ cup sugar. Cut in cold butter until mixture resembles coarse crumbs.
• Set aside ½ cup of the crumb mixture for topping. To the remaining mixture, add baking powder and baking soda and mix well.
• Add milk, egg, and vanilla extract to the batter. Stir until smooth and fully combined.
• Spread the batter evenly into the prepared baking dish. Top with the strawberry rhubarb mixture.
• Mix the reserved crumb mixture with brown sugar and cinnamon. Sprinkle evenly over the top and press lightly.
• Bake for 40–45 minutes, or until a toothpick inserted in the center comes out clean.
• Allow the cake to cool completely before slicing and serving.