In a medium bowl, dissolve the lemon Jell-O in boiling water. Let it cool for 5 to 10 minutes, or until slightly thickened.

While the Jell-O cools, mix 3/4 of the graham cracker crumbs with the melted butter in a medium bowl.

Press the graham cracker mixture firmly into the bottom of a 9x13-inch pan. Set aside. Reserve the remaining graham cracker crumbs for topping.

In a medium bowl, beat the chilled evaporated milk until whipped and fluffy, about 2 to 4 minutes.

In a separate large bowl, beat the cream cheese, granulated sugar, and lemon juice together until smooth.

Add the slightly thickened Jell-O to the cream cheese mixture and mix until combined.

Gently fold in the whipped evaporated milk until the filling is light and evenly mixed.

Spread the filling evenly over the prepared graham cracker crust.

Sprinkle the reserved graham cracker crumbs over the top.

Cover and chill for at least 2 hours, or overnight for best results.

Slice, serve cold, and enjoy.