If making the buttermilk from scratch, pour milk and vinegar into a bowl or measuring jug and let rest for 5-10 minutes.
In a skillet, over medium-low heat, melt the butter. While that's melting, prepare the dry ingredients.Combine flour, baking powder, baking soda, and salt in a bowl, and set aside.
Next, whisk the egg and add the buttermilk, maple syrup, and the melted butter to it and stir to combine. Then add the dry ingredients to the wet and stir to combine.
On medium heat, heat the skillet you used to melt the butter and scoop the batter with a 1/4 cup measuring cup, onto it. Let the pancake cook till golden brown or once you see bubbles appear, about 2-3 minutes. With a wide, flat spatula and with a quick, deft movement, flip the pancake and cook it on the other side. Another 2 minutes.Cook the pancakes in batches of two or three, and once done, enjoy with a pat of butter, a drizzle of maple syrup, and fresh berries.
Notes
Get 1:1 gluten-free baking flour like Bob's Red Mill or King Arthur's for best results.