In a bowl, mix the flour, sugar, baking powder, salt, and poppy seeds.

In a separate bowl, whisk the milk, egg, melted butter, lemon zest, and lemon juice.

Pour the wet ingredients into the dry ingredients and mix until smooth.

Heat a non-stick skillet over medium heat and pour 1/4 cup of batter for each pancake. Cook until bubbles form on the edges, then flip and cook until golden brown.

Place the pancakes on a serving plate, sprinkle with powdered sugar, and garnish with fresh lemon slices.