Gluten-Free Buttermilk Pie with Browned Butter

I first encountered buttermilk pie in Oklahoma City at a restaurant. I had never even heard of it (I guess because it's a traditional southern recipe and I've never spent any time in the south). Well, I loved it! And tried to make some at home. It was delicious and I posted that buttermilk pie recipe here. This time I wanted to make it gluten-free so that Katie could enjoy it. I searched the web for various recipes and decided to just create my own using those as a guide. I used a gluten-free pie crust and non-wheat flour in the filling. I also decided to brown the butter to give it a deeper, warmer flavor. I like to serve it with fresh whipped cream (used honey whipped cream this time) and raspberries. 

Gluten-Free Buttermilk Pie with Browned Butter
1 1/4 cup sugar
1 tablespoon oat flour*
1 tablespoon white rice flour*
1 tablespoon tapioca flour*
1/2 teaspoon xanthan gum*
1/2 teaspoon salt
4 eggs, separated
1 1/2 cups buttermilk
1 1/2 teaspoons vanilla
1 stick butter, melted & cooked until slightly brown, then cooled
1 teaspoon lemon zest
pinch nutmeg

prepared pie crust (I used a gluten-free pie crust mix that I found at my local market, but you can used your favorite pie crust)

*If you don't want or need to make this pie gluten-free, just eliminate the oat, rice, & tapioca flours and the xanthan gum. Replace them with 3 tablespoons all-purpose flour.

Roll the pie crust between two pieces of platic wrap. Remove the top piece of plastic wrap. Turning the crust over, carefully place in a deep pie dish, remove plastic wrap (that was originally on the bottom before you flipped it over), and crimp the edges. Pierce the crust all over with a fork and line the pie crust with parchment or waxed paper. Fill with pie weights or uncooked rice or beans (this just keeps the crust in place and keeps it shape while it cooks).  Bake the crust in the bottom third of the oven at 350 degrees for 10 minutes. Remove the pie from the oven and the pie weights and parchment paper from the crust. You can do this step ahead of time if you like.

Whip the egg whites in a medium bowl using an electric mixer until light and fluffy and soft peaks form (but not stiff peaks).

In a large bowl, combine the sugar, flours, salt, egg yolks, buttermilk, vanilla, cooled melted butter, lemon zest, and nutmeg. You can mix it by hand or use an electric mixer. Fold in the egg whites until incorporated. Pour the filling into the pre-baked pie crust. Bake at 350 degrees for 45 minutes to 1 hour. Sprinkle with large grain sugar as soon as you remove the pie from the oven.

Allow to cool. Serve with whipped cream and raspberries. Dust with powdered sugar if desired. Enjoy!