Line a sheet pan with parchment paper - alternatively you can use a cast iron pan.
Mix the flour, sugar, salt, and baking soda in a large bowl.
With two knives or a paddle attachment on a stand mixer, cut the butter into the dry ingredients until the butter is mixed in well then mix in raisins.
Create a well in the mixture and pour in your egg and buttermilk. Stir the dry ingredients into the liquid slowly with a wooden spoon until it is solid enough to kneed.
Transfer the dough to a lightly floured surface and kneed together to form a ball, careful not to over-kneed the dough. The dough should remain somewhat shaggy looking. If you are using a sheet pan the more circular the better as the bread will spread out a bit while baking.
Transfer the dough to your sheet pan and use a large knife to cut an X into the dough about 1 inch deep.
Bake in oven for 45-55 minutes, or until a cake tester comes out clean. If you are using a cast iron pan it will most likely take 55 minutes as it takes longer to heat up than a baking sheet. The bread should sound hollow when tapped.
Remove to a cooling rack for 5 minutes. Serve warm or at room temperature.