In a large mixing bowl, combine cornmeal, flour, sugar, baking powder, baking soda and salt until combined.
In a medium mixing bowl, whisk together the eggs, buttermilk, and melted butter. Add the buttermilk mixture to the flour mixture and stir until just combined. Add the corn and jalapeño and stir until the ingredients are evenly distributed.
Heat an 8-inch cast-iron skillet in the oven for at least 10 minutes. Butter the skillet then add the batter. Bake the cornbread until a knife inserted into the center comes out clean, about 30 minutes. Let cool.
For the whipped maple butter:
In the bowl of a stand mixer fit with the whisk attachment, add the butter, milk and brown sugar and whisk until the sugar has dissolved and the mixture is light and fluffy. Add the maple syrup and continue to beat until incorporated.
Remove to a small bowl. If not using immediately refrigerate and bring back to room temperature before serving.
To serve:
Serve the cornbread warm and cut into slices then topped with the maple butter.