Preheat your oven to 375 F. Prepare a baking sheet or cast iron skillet with parchment paper laid inside. Don't worry if the parchment paper hangs over the sides, it makes it easier to lift the baked soda bread out later.
Measure the gluten-free flour, baking soda, sugar, and salt into a large mixing bowl and blend with a whisk.
4 cup Gluten Free Flour, 1½ teaspoon Baking soda, 1 tablespoon Sugar, 1¼ teaspoon Salt
Cut in butter until incorporated completely. The flour mixture will appear sandy or coarse in texture. Make a well in the center of the mixture.
6 tablespoon Butter
Add the buttermilk and the egg to the well in the bowl of flour mixture. Using a spatula, fold the wet ingredients with the buttermilk and egg until you have a shaggy dough that is slightly sticky.
1½ cup Buttermilk, 1 Egg
Turn the shaggy dough onto a lightly floured work surface. Using your hands pull the dough together into a large ball, folding it on itself about 5 to 6 times to mix it together and shape into a uniform ball.
gluten free flour
Cris-cross the two pieces of parchment paper, and lay the dough ball in the middle.
Cut an X across the top about ½" deep. Brush top with buttermilk, butter, or leave plain. Place in the center rack the oven.
buttermilk
Bake in preheated oven for 55 minutes. Soda bread is done when the X id no longer wet, and the bread makes a hallow sound. Cool until warm, then serve.