Zest the lemons, then cut in half and juice to measure 2 tablespoons lemon juice.
Measure out the oat milk and add the lemon juice. Set aside for 5-10 minutes to make a buttermilk.
Rub together lemon zest and sugar with your fingers in a large mixing bowl. Add the flour, cornstarch, baking powder, and salt and whisk together.
Add the oat buttermilk, melted vegan butter, poppyseeds, and vanilla extract to the dry ingredients and whisk until fairly smooth, some lumps are ok. Let the batter rest for 10 minutes.
Heat a griddle or fry pan over medium-low heat. When warm, melt a thin layer of vegan butter over the pan, or spray with a thin layer of oil.
Use a 1/3 cup measure to scoop and pour batter onto the pan and let cook until the edges of the pancakes look partially cooked and bottom is golden, flip and cook the second side until golden and pancake is cooked through, about 2-3 minutes each side. Note: the batter is thick, so it may not bubble in the center.
Serve with fresh blueberries and maple syrup or the lemon maple glaze. To make the glaze, whisk together all ingredients then add more lemon juice to taste if desired, or more oat milk to thin to a pourable consistency.
This nutritional information refers to each serving of the entire recipe and not just the products used as ingredients.