In a large bowl, whisk together the flour, sugar, baking powder, baking soda and salt until evenly combined.
In a separate bowl, whisk the buttermilk, melted butter, vanilla and lemon zest until smooth. If the butter firms up into tiny bits from the cool buttermilk, that's completely fine.
Pour the wet ingredients into the dry ingredients and gently fold with a spatula until just combined. A few small lumps should remain, which keeps the pancakes soft and tender.Let the batter rest for 10 minutes. It will thicken and turn slightly bubbly as the baking soda reacts with the buttermilk, and that's what gives you tall, fluffy pancakes without eggs.
Heat a large nonstick skillet or griddle over medium-low heat and grease it lightly with a little butter. The pan is ready when a few drops of water sizzle on the surface.
Pour 1/4 cup of batter per pancake onto the skillet, leaving space between them. Immediately scatter a small handful of blueberries over each pancake and press them in lightly, which keeps the batter from turning purple.
Cook for 2-3 minutes, until bubbles form on the surface and the edges look set. Flip carefully and cook for another 1-2 minutes, until golden brown and cooked through in the center.
Transfer the pancakes to a baking sheet and keep them warm in a 200°F oven while you cook the rest, greasing the pan lightly between batches. Serve warm with maple syrup.