Preheat the oven to 400 F/205 C. Make sure the main rack is in the middle position. In a medium bowl whisk together the flour, salt, baking powder, baking soda, and poppy seeds.
Melt the butter in the microwave or on the stovetop then pour it into a large bowl. Add the sugar and whisk until well combined.
Zest one full lemon and add it to the mixture. Then add about two tablespoons of lemon juice, which is approximately the juice from half of the lemon. Add the vanilla extract as well and mix everything until well combined. Mix in both of the eggs.
Mix in the milk and the yogurt. You can use sour cream too if you don't want to use yogurt.
Finally, mix in the dry ingredient mixture a little at a time until well combined. Start with the whisk, and then switch to a wooden spoon or sturdy spatula. Or use an electric mixer. And now the lemon poppy seed muffin batter is ready to go.
Line a muffin pan with paper cups or spray it with cooking spray. Then use an ice cream scoop or spoons to fill up each cavity with batter. You will probably have enough to make 16 muffins, depending on how much you fill each cavity up.
Now bake the muffins for 12 to 18 minutes until they are slightly golden brown on top and a toothpick comes out clean after being poked in the center. Allow them to cool for 10 minutes in the pan then transfer to a wire rack to cool completely.
Pour the lemon juice into a medium bowl and add the powdered sugar about 1/3rd at a time until incorporated. You may need more depending on the consistency that you want. Dip the tops of the muffin in the glaze. or you can make the glaze even thicker and place it in a piping bag or plastic bag with the corner snipped off and drizzle glaze on the tops of the muffins.
Allow the glaze to set for 5 to 10 minutes, then serve. Enjoy!