Preheat oven to 350 degrees F. Line a standard cupcake tin with paper liners.
In a medium bowl, whisk together the flour, baking powder and salt.
In a large bowl, use an electric mixer to beat together the butter and sugar on medium high until fluffy, about 3 minutes. Add the eggs and beat until incorporated, about 1 minute. Add the yogurt, lemon juice, lemon zest, vanilla and poppy seeds.
Mix in the flour mixture on low speed until just combined, about 1 minute. Be careful not to overmix. The batter will be thick. Spoon it evenly into the prepared tin.
Bake until an inserted toothpick comes out clean or with a few moist crumbs attached, about 20-25 minutes. Remove from tin and let cool completely.
To make the glaze, stir one tablespoon of lemon juice into the powdered sugar. Add additional lemon juice until desired consistency is reached. Drizzle over cooled cupcakes. Cupcakes will keep in an airtight container in the refrigerator for 4 days.