Step 1: In a large bowl, whisk together the gluten-free all-purpose flour blend, granulated sugar, baking powder, baking soda, and salt. Make sure there are no lumps.
Step 2: In a separate medium bowl, whisk together the buttermilk, egg, melted butter, and vanilla extract until well combined.
Step 3: Pour the wet ingredients into the dry ingredients. Stir gently with a spatula or wooden spoon until just combined. The batter should be slightly lumpy; do not overmix, as this can lead to dense pancakes. Let the batter rest for 5-10 minutes while you heat your griddle. This allows the flours to hydrate and thickens the batter slightly.
Step 4: Heat a lightly buttered griddle or non-stick pan over medium-low heat. You can test the temperature by sprinkling a few drops of water on the surface; they should sizzle and evaporate quickly.
Step 5: Pour ¼ cup of batter per pancake onto the hot griddle. Cook for 2-3 minutes per side, or until bubbles appear on the surface and the edges look set. Flip carefully and cook for another 1-2 minutes until golden brown and cooked through.
Step 6: Transfer cooked pancakes to a plate and keep warm while you cook the remaining batter. You can place them in a low oven (around 200°F / 95°C) on a wire rack to prevent them from getting soggy.
Step 7: Serve immediately with your favorite toppings such as maple syrup, fresh berries, or whipped cream. For storing any leftover batter, transfer it to a tightly sealed container and refrigerate for up to 2 days.