Perhaps the best thing about this cornmeal batter is that it can be used on just about any vegetable you choose to bake, though you will have to experiment with the time and oven temperature.
Wash the okra and trim off the stems. Cut a piece of parchment paper to fit a baking sheet. Remove the parchment and place the baking sheet in the oven. Preheat oven to 450F.
In a large mixing bowl, combine all remaining ingredients and mix well. You should have a batter a little thicker than pancake batter. If it seems dry, add a splash of non-dairy milk.
Put a few okra into the batter and stir to coat well. Once the baking sheet is heated, place it on a pot holder or other heat-safe surface next to your bowl of batter. Place the parchment on it. Working quickly, remove each okra pod, allow any excess batter to drip back into the bowl, and place it on the baking sheet, being careful to leave space between each pod. Repeat with as much okra as you can fit on the baking sheet. (If your baking sheet is small, you may need to make two batches; batter can thicken between batches, so add more liquid if necessary.)
Place in the oven. After 15 minutes, remove and gently turn each okra pod. Replace and cook until outsides are brown but not burning, about 15 more minutes. Serve warm with your choice of dipping sauce.
Notes
I used soy milk, which thickens with the addition of lemon juice. If you use another plant-based milk, you may need to add a little extra flour if the batter seems thin.Other flours should work, but I have only tested it at this time with brown rice flour. If you use a different flour, use your judgement about whether the batter needs to be thinned with extra milk or thickened with extra flour.