Preheat your oven to 325°F (163°C). Line the bottoms of three 9-inch round cake pans with parchment paper and grease the sides.

In a large mixing bowl, cream together softened salted butter and granulated sugar until light and fluffy, about 3-4 minutes.

In another bowl, whisk together eggs, buttermilk, and sour cream until well combined.

In a separate bowl, sift together flour, masa harina, baking powder, and salt.

Gradually add the dry mixture to the creamed mixture, alternating with the wet ingredients, mixing just until combined.

Spread the batter evenly among the three prepared pans and bake for 28-33 minutes.

Cool cakes in pans for 10 minutes, then invert onto wire racks to cool completely.

Beat softened butter until smooth. Add honey and mix until combined, then gradually add powdered sugar and cornstarch until fluffy.

Assemble the cake by layering and frosting each layer with honey buttercream.