Preheat your oven to 375°F. Grease a 9-inch round baking pan or 10-inch cast iron skillet.

In a large bowl, whisk together the flour, xanthan gum, baking powder, baking soda, salt, cream of tartar, and granulated sugar.

Incorporate the chopped, chilled butter into the dry mix by flattening each chunk.

Add the raisins and toss to coat.

In a separate bowl, whisk together the buttermilk and eggs until blended.

Make a well in the center of the dry mix, pour in the buttermilk and egg mixture, and mix gently until the dough comes together.

Knead gently with clean hands, adding more buttermilk if any dry spots remain.

Turn the dough out onto a lightly floured surface and shape it into a round approximately 9 inches in diameter.

Place the dough in the prepared pan and slice a large 'X' on top about 1-inch deep.

If the dough feels warm, chill it in the freezer for 10 minutes.

Bake for about 45 minutes or until a toothpick comes out clean.

Cool in the pan for 10 minutes before transferring to a wire rack.