Place a 10-inch cast-iron skillet in oven. Preheat oven to 400°.
In a large bowl, whisk together flour, cornmeal, sugar, rosemary, baking powder, pepper, baking soda, and salt. In a medium bowl, whisk together buttermilk, eggs, and melted butter.
When skillet is hot, make a well in center of flour mixture; add buttermilk mixture, folding just until combined. Fold in 1¼ cups blackberries just until combined. Add softened butter to hot skillet, and swirl until melted and foamy. Pour batter into prepared pan, and smooth top. (Batter should sizzle.) Top with remaining ¼ cup blackberries.
Bake until golden brown and a wooden pick inserted in center comes out clean, 22 to 25 minutes. Let cool in skillet for 15 minutes. Remove from skillet, and let cool on a wire rack. Serve warm with honey and butter.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/blackberry-rosemary-cornbread/