Adjust oven rack to lower-middle position and preheat oven to 425. Spray a muffin tin with non-stick spray or line with cupcakes liners and set aside. Mix flour, poppy seeds, baking powder, baking soda, and salt in a medium bowl.
In the bowl of a stand mixer, beat sugar, butter, and lemon zest on medium speed until light and fluffy. Add eggs, one at a time, beating until combined. Reduce speed to low and add dry ingredients in two installments, alternating with 3 additions of yogurt. DO NOT OVER MIX, or your muffins will turn out hard and tough.
Divide batter evenly among muffin cups. Don't be afraid to fill them all the way to the top!
Bake for 5 minutes at 425, and then lower oven temperature to 375. Bake another 15 to 18 minutes, or until muffins are golden brown and a toothpick inserted in the center comes out clean.
Remove muffins from tin to wire rack and allow to cool for 5 minutes. Meanwhile, combine powdered sugar and lemon juice in a small bowl. Drizzle over cooled muffins.