Gluten Free Cornbread

I have no idea where my mom got this recipe, so I'm probably copying without credit. Sorry 'bout that, but it's tasty and I need it written in a place where I can find it!

1/4 cup sorghum flour
1/4 cup tapioca starch
1/4 cup potato starch
1/4 cup sweet rice flour
1/4 cup sugar
4 teaspoons baking powder
3/4 teaspoon salt
1 teaspoon xanthan gum
1/4 cup shortening (not butter)
2 large eggs
1 cup milk
1 cup yellow cornmeal

Preheat oven to 425.

Combine the flours by sifting them into a large bowl. Add remaining dry ingredients and stir.

Cut the shortening into the flours, the way you would when making pie dough. You should end up with walnut-sized pieces in a sandy flour.

Combine the eggs and milk in a small bowl. Make a well in the center of the dry ingredients and pour in the liquid. Stir with a rubber spatula until everything is combined.

Stir in the cornmeal, whisking fast, until just combined. Do not overstir.

Pour into greased 9x9 pan and bake for 20-25 minutes, until the sides of the cornbread are slightly shrinking back from the edge of the pan and a toothpick comes out clean.