Preheat the oven: Set the oven to 350°F (175°C) and grease a standard muffin tin or line it with cupcake liners for easy cleanup.

Mix the wet ingredients: In a large bowl, whisk together the sweetened condensed milk, lemon juice, eggs, melted butter, and vanilla extract until smooth.

Add the dry ingredients: Gently fold in the self-rising flour and lemon zest. Mix until just combined—don’t overmix.

Fill the muffin tin: Pour the batter into the muffin cups, filling each about ¾ full.

Bake: Bake for 18-22 minutes, or until the tops are lightly golden and the centers are set. Use a toothpick to check for doneness—if it comes out clean, they’re ready.

Cool & serve: Let the pies cool in the tin for about 10 minutes, then transfer to a wire rack to cool completely. Serve chilled or at room temperature.