Add together flour, baking soda, salt, sugar, poppy seeds and lemon zest in a bowl
In another bowl combine sour cream, egg, melted butter and vanilla. If using Greek yogurt, batter will be thicker.
Add to dry ingredients and stir just until moistened, do not over stir
Spoon batter evenly into prepared muffins pans (creased or liners) Fill 2/3 full. About 1/3 cup of batter.
Bake at 400 degrees F for 12-15 minutes or until lightly brown
Remove from pan and cool on rack
Glaze
Add together powdered sugar, lemon juice and vanilla in a bowl, stir until smooth.
Drizzle the glaze over top of muffins
Notes
Use fresh lemon. Fresh lemon juice and lemon zest will give you the best, brightest lemon flavor. Be sure to zest the lemon before you juice it—it’s much easier!
Don’t overmix. Mix the batter just until the dry ingredients are incorporated. Overmixing can give you dense or tough muffins instead of light, tender ones.
Boost the lemon flavor. When adding the lemon zest, rub it into the sugar with your fingers before mixing the batter. This helps release the oils in the zest and gives the muffins even more lemon flavor.
Fill the muffin cups evenly. A cookie or muffin scoop works great for dividing the batter evenly so your muffins bake at the same rate. Use about 1/3 cup batter per muffin.
Let them cool before glazing. If the muffins are too warm, the lemon drizzle will melt right off. Allow them to cool before adding the glaze.
For a thicker glaze. Add a little more powdered sugar. For a thinner glaze, add lemon juice a teaspoon at a time until you reach the consistency you like.
Muffin batter is meant to be thick. You should be able to stand a fork or spoon up in it. If you think it is too thin, add just a bit more flour. A thicker, stiffer batter will give you a taller, puffy style muffin but you will still have a light and tender muffin.