Heat oven to 400 degrees and lightly butter baking pan. In bowl, combine flour, cornmeal, sugar, baking powder, baking soda and salt.
In separate bowl, whisk pumpkin puree, eggs, butter, honey, buttermilk and orange zest. Stir flour mixture into pumpkin mixture until moistened; transfer to prepared baking pan.
Bake until cornbread pulls away from sides of pan and toothpick inserted into center comes out clean, 20-22 minutes. Cool in pan 5 minutes. Remove from pan and cool on wire rack at least 10 minutes before cutting.