Preheat oven to 400°F and place a cast iron skillet inside to heat for 10-15 minutes
In a large bowl, whisk together flour, baking soda, salt, and maple sugar or white/brown sugar
Freeze butter for 10 minutes until very firm, then grate it directly into the flour mixture using a box grater
Gently toss with your fingers until the butter shreds are coated in flour and the mixture looks light and fluffy
Pour in buttermilk and stir just until a shaggy dough forms, being careful not to overmix
Turn dough onto a lightly floured surface and gently shape into a round loaf about 2 inches thick without kneading
Carefully remove the hot skillet from the oven, lightly butter it, and place the dough round in the center
Using a sharp knife, cut a deep X across the top of the loaf about ½ to ¾ inch deep
Bake for 35-40 minutes until the loaf is deep golden brown and the bottom sounds hollow when tapped
While bread bakes, stir together melted butter, honey, and sea salt
As soon as bread comes out of the oven, brush generously with honey butter glaze, wait 2-3 minutes, then brush one more light layer
Let the bread cool for 10-15 minutes, then slice and serve warm
