In a large bowl, whisk together the flour, baking powder, and salt. In a small bowl, combine the sugar and lemon zest. Rub together with your fingers until fragrant. Whisk into the dry ingredients.
In a medium bowl, whisk together the yogurt, milk, lemon juice, eggs, oil, and vanilla. Add the wet ingredients to the dry ones, mixing only until combined. Stir in the poppy seeds.
Heat a griddle pan or non-stick skillet over medium heat. Spray with cooking spray. Pour about 1/4 of a cup of pancake batter onto the hot griddle pan, spacing out the pancakes a few inches from each other. When the pancakes start to bubble up, flip and cook until pancakes are slightly golden brown. Serve warm with butter, maple syrup, fresh fruit, or jam-if desired.