Preheat oven to 350°F (175°C)
Bring 4-6 quarts of water to boil
Cook lasagna noodles according to package instructions (if using dry);
bring to room temperature or refrigerate
In a large bowl, mix cream cheese, 2 tablespoons powdered sugar, and 2 tablespoons fresh lemon juice until smooth
In another bowl, combine sweetened condensed milk, evaporated milk, remaining 3/4 cup lemon juice, and remaining 1/2 cup powdered sugar
In a 9×13-inch baking dish, layer 1/3 of the lasagna noodles, 1/3 of the cream cheese mixture, and 1/3 of the lemon milk mixture
Repeat layers twice
Spread melted butter in an even layer over the top
Bake for 25 minutes
Let cool to room temperature, then refrigerate for 4 hours or overnight