1. Preheat the oven to 350°F and grease a standard 12-cup muffin tin very well.

2. In a large bowl, whisk together the sweetened condensed milk, whole milk, eggs, melted butter, lemon juice, lemon zest, and vanilla extract until smooth.

3. Add the flour, granulated sugar, and salt, then whisk until the batter is fully combined and mostly lump-free.

4. Pour the batter into the prepared muffin cups, filling each about three-quarters full.

5. Bake for 22 to 28 minutes, until the tops are lightly golden and the centers are mostly set with a slight jiggle.

6. Let the pies cool in the pan for 15 to 20 minutes, then carefully remove and transfer to a wire rack.

7. Once cooled, dust with powdered sugar and garnish with extra lemon zest if desired.

8. Serve chilled or at room temperature.