Makes 6 to 8 servings
1/4 cup water
1 1/2 teaspoons cornstarch
1/3 cup plus 1/2 cup sugar
2 cups chopped fresh rhubarb stalks (10 ounces)
1 cup chopped fresh strawberries (5 ounces)
1 cup Nutri Flour Blend
1 3/4 teaspoons baking powder
1/2 teaspoon coarse kosher salt
1 large egg
1/2 cup whole milk
1 stick (1/2 cup) unsalted butter, melted and cooled slightly
1 teaspoon pure vanilla extract
Put oven rack in middle position and preheat oven to 400°F.
Butter an 8-inch square glass or ceramic baking dish.
Stir together water, cornstarch, and 1/3 cup sugar in a small saucepan, then stir in rhubarb. Bring to a simmer, stirring constantly, then simmer, stirring occasionally, 3 minutes. Remove from heat and stir in strawberries.
Whisk together flour, baking powder, salt, and remaining 1/2 cup sugar in a bowl.
Whisk together egg, milk, butter, and vanilla in a large bowl, then whisk in flour mixture until just combined.
Reserve 1/2 cup fruit mixture, then add remainder to baking dish and pour batter over it, spreading evenly.
Drizzle reserved 1/2 cup fruit mixture over batter.
Bake until a wooden pick inserted into centre of cake portion comes out clean, 25 to 30 minutes. Cool in pan on a rack 5 minutes before serving.