Strawberry Rhubarb Upside Down Cake – Wisconsin Local Food

Ingredients

• 2 1/2 sticks unsalted butter, at room temperature, more to grease pans
• 1 1/2 pounds rhubarb, rinsed and sliced into 1/2-inch cubes (about 4 cups)
• 2 cups strawberries, halved or quartered if large
• 4 teaspoons cornstarch
• 1 1/2 cups granulated sugar
• 1/2 cup light brown sugar
• 2 cups cake flour
• 1 1/4 teaspoons baking powder
• 1/2 teaspoon fine sea salt
• Zest of 1 lemon, grated
• 1 teaspoon vanilla extract
• 4 large eggs
• 1/3 cup sour cream
• 2 teaspoons lemon juice