In a medium-sized bowl, mix the flour, baking powder, salt, and baking soda together. Mix well so there are no clumps of baking powder. Make a well in the center.
Add the oat milk, vegan melted butter, vanilla, maple syrup, and applesauce (if using). Mix the wet ingredients with the flour mixture until just combined.
Cook the pancakes until brown on each side. Wait for small bubbles to form in the center of the pancakes, then flip. Cook the other side until golden brown.