Cake with A-Plum

I made this cake a few weeks back in the throes of my "We're going to Paris for Christmas, so let's eat French food" fit. It's from Ina Garten's Barefoot in Paris cookbook. I'm not usually into those Food Network AM ladies (Giada, Rachel, Ina, etc...), but this book has proved to be a solid source of good, easy, French (sometimes French-lite) recipes. And since we had a ton of end of the season plums, this seemed like a good recipe to use them in. I mean, who doesn't like cake?
As per usual, I tweaked the recipe a bit - subbing these Emerald plums for the purple "prunes" Ina asks for, as well as cutting them into slices and making this cool spiral pattern v. her idea of just halving them. This seemed like a prettier, not to mention more fork-friendly, way to go.
This is the end result. Noah and I had a few slices warm out of the oven and shared the rest with our friends a few days later at an Election Night party (told you this post was overdue). Everyone voted "yes" on Prop Plum Cake.

Oh yes, the fruit part seems to invite many, many variations. Ina suggests pears as an alternative. I think apples, persimmons and cherries would also be lovely. And I'm seriously considering a cranberry version for Thanksgiving.

Plum Cake "Tatin"
from Barefoot in Paris by Ina Garten

6 tbsp. unsalted butter, at room temp, plus extra for greasing the dish.
10 to 12 purple "prune" plums, cut in half and pitted (I used 8 or so Emerald plums, cut into 1/8ths)
1 3/4 c. granulated sugar, divided
2 extra large eggs, at room temperature
1/3 c. sour cream (I used 1/3 c. non-fat greek yogurt)
1/2 tsp. grated lemon zest (I used grated grapefruit zest since we were out of lemons)
1/2 tsp. pure vanilla extract
1/2 tsp. baking powder
1/4 tsp. kosher salt
Confectioners' sugar

Preheat the oven to 350 degrees. Generously butter a 9-inch glass pie dish and arrange the plums in the dish, cut side down (or in a circular pattern of slices, as I did).

Combine 1 c. of the granulated sugar and 1/3 c. water in a small saucepan and cook over high heat until it turns a warm amber color, about 360 degrees on a candy thermometer. Swirl the pan, but don't stir. Pour evenly over the plums.

Meanwhile, cream the 6 tablespoons of butter and the remaining 3/4 cup of granulated sugar in the bowl of an electric mixer fitted with the paddle attachment, until light and fluffy. Lower the speed and beat in the eggs one at a time. Add the sour cream, zest and vanilla and mix until combined. Sift together the flour, baking powder, and salt, and, with the mixer on low speed, add it to the butter mixture. Mix only until combined.

Pour the cake batter evenly over the plums and bake for 30 to 40 minutes, until a cake tester comes out clean. Cool for 15 minutes, then inverth the cake onto a flat plate. If a plum sticks, ease it out and replace it in the design on top of the cake. Serve warm or at temperature, dusted with confectioners' sugar.