Although a food processor is the easiest method, this can easily be make this by hand, mixing in the water and butter with a spatula and then kneading by hand.
In a large bowl, whisk together the flour, cornmeal, salt, sugar, and yeast; add water and melted butter and, using a food processor, on low speed, using a dough hook, mix until fully combined, about 1 to 2 minutes, scraping sides and bottom of bowl occasionally.
Increase speed to medium and knead until the dough is glossy and smooth and pulls away from sides of the bowl, 4 to 5 minutes.
Coat a large bowl with 1 teaspoon olive oil; using a greased spatula, transfer the dough to the bowl, turning to coat the dough in oil; cover tightly with plastic wrap; let rise at room temperature until nearly doubled in volume; around 45 to 60 minutes.