In a spacious mixing bowl, combine the all-purpose flour, poppy seeds, granulated sugar, baking powder, and salt. Whisk them together thoroughly until they are evenly blended.
In a separate bowl, whisk together the buttermilk, the large egg, melted butter, lemon zest, and freshly squeezed lemon juice until the mixture is smooth and well integrated.
Gently pour the wet mixture into the bowl with the dry ingredients. Carefully fold the two together using a spatula or wooden spoon. Be cautious not to overmix; a few small lumps in the batter are perfectly fine and will help keep the pancakes fluffy.
Heat a non-stick skillet or griddle over medium heat. Lightly grease the cooking surface with a small amount of butter or cooking spray to prevent sticking.
For each pancake, pour 1/4 cup of the batter onto the hot skillet. Allow the pancakes to cook until bubbles form on the surface and the edges begin to firm up, approximately 2 to 3 minutes.
Carefully flip the pancakes using a spatula and cook for an additional 2 to 3 minutes, or until they are golden brown on both sides. Adjust the heat if necessary to avoid burning.
Continue the process until all of the batter has been cooked, ensuring to re-grease the skillet as needed for each batch.
Notes
For an appealing presentation, stack the pancakes high and garnish with lemon slices and poppy seeds.