Preheat oven to 350°F. Grease or line a 6-cup muffin tin.
Add milk, eggs, lemon zest, lemon juice, vanilla, sugar, flour, salt, and melted butter to a blender.
Blend until completely smooth.
Pour evenly into prepared muffin cups.
Bake 20–25 minutes, until lightly golden and just set in the center (a slight jiggle is okay).
Cool completely before removing from the pan.
Dust with powdered sugar before serving.
Chill for a firmer custard texture or serve at room temperature for extra creaminess.
