Preheat oven to 375°F and grease a cast iron skillet or baking dish with butter or oil.
In a large bowl, whisk together flour, baking soda, baking powder, and salt.
Coat the butter stick in the dry mixture and grate it in using a cheese grater.
Add sourdough discard and honey, then stir lightly with a spatula.
Gradually add iced water, ¼ cup at a time, until a shaggy dough forms. Add flour if too sticky.
Knead using a stand mixer with a dough hook (2–3 min) or by hand.
Cover with a towel and chill for 10 to 15 minutes in the fridge while you prepare the filling.
For the filling, mix butter, brown sugar, and vanilla until smooth. I use a scraper spatula.
On a floured surface, roll dough into a rectangle with 1/4 inch thickness. Spread filling evenly using a spatula on top.
Roll tightly from the long side, seal the edge, and slice into 6 even rolls using floss or a sharp knife.
Arrange rolls in the prepared dish, slightly spaced apart.
Bake 25–35 minutes, until golden and cooked through.
For the glaze, whisk together melted butter, sugar, salt, vanilla, honey, and cream until smooth.
Pour over warm rolls and serve.