Preheat the oven to 350 degrees F. Spray a 15 cup bundt pan with nonstick baking spray and set aside.
Remove the corn from the cob and place onto a parchment lined baking sheet. Pour melted butter on top of the corn and toss together until all of the corn is coated. Bake in the oven for 15-20 minutes, until softened. Remove and set aside.
Reduce oven temperature to 325 degrees F.
In the bowl of a stand mixer fitted with the paddle attachment, combine salted butter, oil, and sugar. Cream together on medium speed for 5-7 minutes, until lightened in a color and fluffy. Scrape down the sides of the bowl halfway through.
Reduce mixer to low speed and begin adding eggs, one at a time, ensuring that each egg is fully incorporated prior to adding the next.
In a medium mixing bowl whisk together the wet ingredients. Combine sour cream, buttermilk, and creamed corn. Mix together.
In a separate bowl, whisk together all purpose flour, masa harina, cornmeal, nutmeg, baking powder, baking soda, nutmeg, and kosher salt. Add in the roasted corn and toss together so that the corn is coated in the flour.
Add half of the dry ingredients to the stand mixer and mix until just combined, about 10-15 seconds. Scrape down the sides of the bowl and then add in all of the buttermilk/corn mixture and continue to mix until just combined, about 10-15 seconds. Finally, add the remainder of the dry ingredients and mix until a smooth batter forms.
Scrape down the sides and bottoms of the bowl again, ensuring that all of the ingredients are fully incorporated. Pour batter into the prepared pan.
Bake on the middle rack of the oven for 65-75 minutes, until a toothpick comes out clean. Allow the pound cake to cool in the pan for 10 minutes, then turn over onto a wire rack. Let the cake cool completely.
In a large bowl, combine butter and honey. Use an electric mixer to mix together until combined, then add in powdered sugar and sour cream and mix until smooth, about 1 minute.
Add cream to a piping bag or use a spoon to dollop on top of the cooled cake.
Notes
Room-temperature ingredients are key! With a heavy batter like this, you'll want to be sure that everything comes together smoothly. Room temperature ingredients ensure that there's no curdling of the batter. Don't skip this!
Cream your butter and sugar for the full 5 minutes. This traps in air and helps the cake rise in the oven for a nice fluffy crumb!
Test for doneness early. Corn-based cakes can go from perfect to dry quickly. Start checking with a toothpick about 5–10 minutes before the suggested bake time.
Use a kitchen scale to measure the ingredients. This allows for the most precise measurements, ensuring that the cake turns out perfectly!
Don't add the honey buttercream on top until the cake is fully cooled to room temperature.