Preheat your oven to 375 degrees F. Take a sheet pan and line it with parchment paper.

Combine your flour, baking soda, sugar, and salt into a bowl of an electric mixer. Add in your butter and mix the substances on low speed until the flour and butter have been mixed together.

Take a fork and lightly beat the egg, buttermilk, and orange zest together inside of a measuring cup. While the mixer is on low speed, slowly add in the buttermilk mixture to the flour.

Combine the currants and the 1 tablespoon of extra flour, and mix them into the dough. It's supposed to be wet.

Dump the dough onto a board that has been well floured, and knead it inro a round load. Place said loaf onto the prepared sheet pan, and cut on X into the top of the bread with a knife.

Bake for 45 to 55 minutes, or use a cake tester until it comes out clean. Tap the loaf, and it should have a hollow sound.

Leave to cool on a backing rack. Serve warm or at room temperature.