Preheat oven to 400°F. Line a 12-cup muffin pan with paper liners or spray with baking spray.
In a large bowl, beat the sugar and butter for 2-3 minutes until creamy and light.
1/2 cup salted butter, 1 1/4 cups granulated sugar
Add lemon zest and eggs. Beat well, then scrape the bottom and sides of the bowl. Add the lemon juice, sour cream, oil, and vanilla extract and mix again to combine.
Zest of 3-4 lemons, 1/4 cup lemon juice, 3 large eggs, 1 cup sour cream, 1/4 cup vegetable oil, 2 teaspoons vanilla extract
Add flour, baking powder, baking soda, salt, and poppy seeds. Stir by hand just until combined. Be careful not to overmix.
3 1/2 cups all-purpose flour, 1 Tablespoon baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon salt, 3 Tablespoons poppy seeds
Divide the batter evenly between the muffin cups, filling them all the way to the top. Sprinkle each muffin with 1/2 teaspoon of sugar.
Bake for 20-22 minutes until golden brown on top. Remove and cool completely.
While the muffins are cooling, make the glaze by whisking the powdered sugar with enough lemon juice to get a consistency you like. Dunk the tops of each muffin in the glaze or use a pastry brush to brush it on, then let the glaze set before serving.
1 1/2 cups powdered sugar, 3-4 Tablespoons lemon juice