Preheat your oven to 375 degrees F (190 degrees C). Place the baking pan you will use for the cornbread in the oven (I used a 10-inch cast-iron skillet).
Whisk the cornmeal, salt, baking powder, baking soda, and sugar together in a large bowl until well mixed.
Combine the ingredients for the vegan buttermilk, those for the vegan eggs, and all but 1 Tablespoon of the melted butter in another bowl. Stir until well combined.
Combine the mixtures in the dry and liquid bowls. Mix until just combined; do not over-stir.
Carefully remove the baking dish (or skillet) from the oven - it’s hot. Use the remaining 1 Tablespoon of butter to grease the bottom and sides of the pan.
Pour the cornbread mixture into the pan. Use a spatula or scraper to smooth the surface of the mixture.
Bake until a toothpick inserted into the center of the pan comes out clean, about 45 minutes. Let the cornbread rest in the pan for 15 minutes before serving.