Upside-down Polenta Plum Cake

Our plum trees been a bit over-active lately, so I'm trying to take advantage of the plums while they last. The author also suggests that rhubarb, raspberries, blackberries, cranberries, apricots, and pineapple could be a good alternative for this cake. Per her suggestion, I also added a bit of ground cardamom to the batter to give it a little bit extra, but she also recommends citrus zest or ground nutmeg as additions. This cake is good cool, but even better served warm. Make sure you line your pan well or stick it on a baking sheet because I experienced some leakage.

One year ago: Berry Summer Bundt Cake
Two years ago: Chipotle Pork Cheeseburgers
Three years ago: Vodka Cream Pasta

Upside-down Polenta Plum Cake (from Cook This Now)

Ingredients
1 3/4 lbs plums, rinsed, pitted, and sliced 1/2" thick
1 1/2 cups plus 2 tbsp sugar, divided
3/4 tsp kosher salt
1 cup fine cornmeal
1/2 cup all-purpose flour
1 1/2 tsp baking powder
1 cup unsalted butter, at room temperature
4 large eggs
1/3 cup sour cream or plain yogurt
2 tsp vanilla extract

1. In a large skillet over medium-high heat, cook plums, 1/2 cup plus 2 tbsp sugar, and 1/4 tsp salt, stirring until plums are tender and liquid begins to reduce, 20 minutes.
2. Heat oven to 350F. Line a 9" springform pan with parchment and grease well.
3. Spread plum mixture into pan.
4. In a bowl, whisk together cornmeal, flour, baking powder, and 1/2 tsp salt.
5. In bowl of an electric mixer, cream butter and remaining 1 cup sugar until light and fluffy.
6. Add eggs one at a time to butter and beat to combine.
7. Beat in sour cream and vanilla.
8. Use a spatula to fold in dry ingredients. Scrap batter on top of plums (it will be extremely thick) and smooth as best you can with the spatula.
9. Bake until cake is golden and cooked through, 45 - 55 minutes.
10. Cool in pan for 10 minutes. Flip onto a plate and unmold. Serve warm.