Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius) and prepare muffin tins with 18 paper liners (this recipe makes about 18 to 20 muffins).
Add the all purpose flour to a large bowl and whisk together with the sugar, baking soda, salt and poppy seeds.
In a large liquid measuring cup, measure the milk and the oil.
Add the sour cream and eggs, along with the lemon zest and juice, and whisk all the wet ingredients together well.
Add the wet ingredients to the dry ingredients and mix with a wooden spoon or spatula just until combined and no streaks of flour remain.
Divide the batter between the 18 or 20 prepared muffin cups, filling them about 2/3 full with the batter.
Bake at 350 degrees Fahrenheit (175 degrees Celsius) for about 20-24 minutes or until the muffins are a light golden brown and a toothpick inserted into the middle of one of the muffins comes out clean.
Let the muffins cool in their tins until almost completely cooled.
Whisk together the powdered sugar and lemon juice (add a few more drops of lemon juice, if necessary) to form a glaze.
Brush the glaze onto the tops of the muffins and let the glaze set fora few minutes before serving.