If you end up purchasing Joy's cookbook....you'll find the recipe on page 113, titled Buttermilk Skillet Cake with Walnut Praline Topping. I happen to not like walnuts, so I automatically swap them out for pecans whenever called for in a recipe. I made the cake in an 8" skillet as instructed. Which overflowed. I think it should've been a 10" skillet instead. Either way, this cake is flippin' amazing. Light, fluffy....not too sweet because the praline has that roll. And it does it well!
Preheat your oven to 375' F. Grease and flour an 8" over safe (ie: cast iron) skillet, along the bottom and up the sides. Joy says a 9" cake pan will work as well. Don't make up your mind yet....please.
In a medium bowl whisk together the flour, baking powder, baking soda and salt. Set aside.
In another medium bowl, with a stand or hand mixer, cream together the granulated sugar and butter until fully incorporated, about 3 minutes.
Add the egg and yolk, one at a time, beating for 1 minute between the two.
Beat in the vanilla.
Now....with the mixer on low, add half of the flour. Beat until incorporated. Add the buttermilk, and beat again until incorporated. Finally, beat in the remaining flour until almost fully incorporated. Stop beating and continue with a spatula to fully incorporate the flour.
Pour / spoon the batter into your prepared pan.
Smooth the batter in the pan evenly. (Put a pan on the bottom rack. Just in case.) Bake for 30 minutes until a toothpick inserted in the center comes out clean.
While things of unknown magnitude are going on in the oven....you should make the pralines: Combine the brown sugar, butter, cream and salt in a medium saucepan. Bring to a soft boil and let boil for 3 minutes. Keep an eye on it. It likes to get a little rambunctious....just stir it down.
After 3 minutes, remove from heat and stir in the vanilla and nuts. Allow to set for about 20 minutes to thicken up a bit.
Once the cake is out of the oven, and while it's still warm pour the praline over the whole thing.