Adjust oven rack to top third position; preheat oven to 400 degrees. Coat 12-cup muffin pan with vegetable spray. Thoroughly mix flour, sugar, poppy seeds, baking powder, baking soda and salt in large bowl. In medium bowl, whisk eggs, buttermilk, oil and lemon zest until blended. Pour liquid mixture over dry ingredients and fold in with rubber spatula just until combined; do not overmix. Spoon batter into prepared muffin cups, dividing evenly. Bake 20 minutes or until tester comes out clean. Meanwhile, stir lemon juice and sugar in small bowl until sugar is dissolved; set aside. When muffins are removed from oven, pierce tops in several places with toothpick (or carefully with fork). Restir lemon glaze, then slowly drizzle about 1 tablespoon of lemon mixture over each muffin. Allow muffins to cool in pan for 10 minutes to absorb syrup, then remove to rack to cool.