Strawberry Upside-Down Cake

1. Preheat the oven to 350°F.
 Butter a 9-inch cake pan with 3 tablespoons butter. (Lightly coat the sides and use more butter on the bottom of the pan.)

2. Sprinkle 3 tablespoons brown sugar into the base of the cake pan in a nice, even coat. Layer the strawberries on top of the sugar in the pan.

3. In a large bowl, whisk the whole-wheat flour with the all-purpose flour, baking powder, baking soda, salt and cinnamon.

4. In the bowl of an electric mixer fitted with the paddle attachment, cream the remaining 8 tablespoons butter and ½ cup brown sugar until light and fluffy, 4 to 5 minutes. Add the egg and vanilla, then mix until well combined, 1 to 2 minutes more. 


5. Add the dry ingredients to the mixing bowl and mix just until combined.
 Add the yogurt and mix just until incorporated. Pour the finished batter over the strawberries. (The batter will be a little thick, so drop a few dollops into the pan and use a spatula to spread it evenly.) 


6. Bake the cake until a toothpick inserted into the center comes out clean, 25 to 30 minutes. Let the cake cool for 15 minutes inside the pan, then run a spatula around the edge and invert the cake onto a platter or stand. Cool completely before eating.