Preheat your oven to 350 degrees. Place your graham crackers in a food processor. Pulse until very finely crushed.

Measure 1 1/2 cups of crumbs into a mixing bowl. Add sugar and melted butter; stir till the mixture resembles wet sand.

Pour crumbs into a deep 9″ pie dish. Press up the sides and into the bottom of the pan. I use my fingers, but you can use a clean measuring cup.

Bake at 350° for 8 minutes. Remove from the oven and turn the heat down to 325 degrees. While the crust is baking, prepare the filling.

Wash the lemons and wipe dry. Zest and juice the lemons.

Whisk the sweetened condensed milk and egg yolks in a large mixing bowl until smooth. Add the lemon juice and zest, and whisk until well combined. Pour into the hot crust.

Turn the oven down to 325°. Bake at 325° for 25-35 minutes, or until the middle is barely set.

Let cool on a wire rack for 25-30 minutes, then chill for 1 1/2-2 hours, or until completely set. You can chill it overnight.

When ready to serve, place a glass or metal mixing bowl and your beaters in the freezer for 5-10 minutes.

Pour the cream into the cold bowl, then add the powdered sugar and vanilla. Beat with an electric mixer at high speed until it holds a peak when you pull the beaters out of the bowl.

Spread the whipped cream over the pie. Slice and serve. You can garnish with fresh lemon slices if desired.