Preheat your oven to 250 F.
Line a baking sheet with parchment paper. Lightly spray the paper with non-stick spray.
Combine the cornmeal, masa, 3 tablespoons of the sugar, vanilla extract, and all of the salt.
Add 2 cups of boiling water and stir until blended. Add more water as needed, getting the batter to a consistency just a little thinner than that of pancake batter.
Pour the batter out onto the lined baking sheet and spread out evenly. Try to get it as thin as possible (mine was a bit thick, but you're aiming for 1/8" if possible).
Sprinkle the batter with the remaining sugar.
Bake for 45 minutes, turning every 15 minutes. The batter will dry out and start to crack. If your batter is thick like mine you might have to bake it a little longer.
Remove from the oven and let cool.
Break up the corn into bite-sized pieces. It's like breaking up brittle, but you want smaller pieces.
Return to the oven and bake another hour or until fully dried.
Remove and let cool completely. The flakes will get a bit crunchier after cooling.
Keep in an airtight container.