Preheat oven to 375ºF.
In a bowl mix the butter and sugar.
Beat in the eggs, and the lemon juice.
Add the milk, half the flour, and baking powder.
Stir in the remaining flour, the poppy seeds, cinnamon, and vanilla.
Mix well until no lumps are left.
Line up the muffin pan with baking cups.
Fill the cups with the batter.
Place in the oven for 25 minutes.
Remove from the oven and take out the muffins.
Add some poppy seeds on top and garnish with the glaze using a piping bag.
Serve and enjoy.