Preheat oven to 350°F (175°C). Lightly grease your muffin tin or line with cupcake liners.
Blend or whisk: In a bowl, combine sweetened condensed milk, eggs, melted butter, lemon juice, lemon zest, milk, vanilla, and salt. Whisk until smooth.
Add flour: Mix in flour until batter is evenly combined. You can also blend all ingredients together for a silkier texture.
Pour batter evenly into muffin cups, filling each about ¾ full.
Bake for 22–26 minutes, or until the centers are set and tops are just golden.
Cool in the pan for 10 minutes, then carefully remove and let cool fully on a wire rack.
Dust with powdered sugar before serving. Optional: add whipped cream or berries on top!