Mix together yeast, honey and water in a glass bowl. Allow to sit for 5–10 minutes, until bubbly and active.
Thoroughly whisk brown rice flour, sorghum flour, tapioca, psyllium fiber, baking powder and salt in the bowl of a stand mixer. Add yeast mixture, starter, water, egg and vinegar. Attach dough hook and blend on low speed until well mixed, then increase to medium speed and knead dough for 5 minutes.
Place English muffin molds on a parchment-lined baking sheet. Evenly sprinkle the gluten free cornmeal into each mold. Place about ⅓ cup dough into each mold and press with wet fingers to flatten. Cover and allow to rise until doubled in size, 1–2 hours.
Preheat a large nonstick skillet over medium-low heat. Preheat oven to 325°F and remove muffins from molds. Spray pan with oil and cook muffins for 3 minutes, or until browned. Flip and cook the other side for 3 minutes, or until browned. Return browned English muffins to parchment-lined baking sheet and bake for 15–20 minutes, or until the internal temperature has reached 205°F.