If using farmed duck breast, pound to an even 1/2-inch thickness.
Pierce the duck all over with a fork or jaccard to tenderize.
In a non-reactive bowl, mix buttermilk and hot sauce (if using). Add duck breasts. Marinate 1 hour at room temp or up to 3 hours refrigerated.
Mix flour, cornmeal, cornstarch, and spices in a large bowl. Pour half into a baking dish.
Remove duck breasts from buttermilk, shake off excess, and dredge thoroughly. Add remaining breading and press it into the meat.
Rest breaded duck 30–60 minutes at room temp.
Heat oil in a deep cast iron skillet to 325°F.
Pan fry in batches: 5 minutes per side, then 5–7 minutes on the second side, until golden brown and cooked through.
Rest on a rack 5 minutes before serving.