Method:
Preheat the oven to 350 degrees fahrenheit. Melt the butter over medium-low heat in the cast-iron skillet. Transfer 1/2 cup of melted butter in a small bowl. Add the brown sugar to the reserved butter in the skillet and stir until combined; spread in an even layer and remove from the heat.
Wash and dry the rhubarb; remove the ends and cut each stalk into 2-inch pieces. Arrange the rhubarb in an even layer on top of the sugar in the skillet; trim the pieces as needed so that they don’t overlap.
- Prepare the dry ingredients
In a medium bowl, whisk together the flour, cornmeal, baking powder, baking soda and 1/4 teaspoon of salt until combined; set aside.
- Prepare the wet ingredients
In a large bowl, whisk together the sugar, eggs, and vanilla until combined. Alternate between whisking in the dry mixture and the buttermilk, starting and ending with the dry mixture.
Stir in the reserved melted butter a little at a time, ensuring each addition is fully incorporated before adding the next. Using a rubber spatula, scrape the batter into the prepared skillet and spread it evenly over the rhubarb.
Bake for about 35 minutes, or until the cake is golden brown and cooked through in the center. Remove from the oven and let the cake cool for 15 minutes in the skillet. Using a large plate or serving platter, invert the cake out of the skillet and let it cool for at least 30 minutes before slicing into even pieces. Serve with a scoop of softened ice cream on the side.
