PREP: Preheat oven to 350 degrees F. Spray a 9-inch pie dish with non-stick spray and set aside.
CRUST: Start by melting the butter in a microwave-safe bowl. Once melted, set aside to cool for 5 minutes. (Hot butter will cause a greasy crust.) In a blender or food processor, process the graham crackers until they are all fine crumbs (re-blend any large chunks). Measure to get a level 1 and 3/4 cups of crumbs and add to a large bowl. Add in the sugar and salt. Use a spatula to scrape every bit of the cooled, melted butter into the bowl. Gently stir with a wooden spoon until well combined. Pour the mixture into the prepared pan. Press the crumbs into the bottom of the pan and then up the sides. Use the bottom of a flat 1-cup measuring cup to thoroughly compress the graham cracker crumbs into a firm crust. Bake in the preheated oven for 8 minutes and set aside to cool.
PIE FILLING: Using a mixer (stand or hand mixer), mix both cans of sweetened condensed milk, egg yolks (reserve whites for another recipe or discard), lemon juice, lemon extract, and salt together. Beat on medium speed for 2-4 minutes or until completely combined and smooth.
BAKE: Pour mixture into the baked pie crust and bake for 12-17 minutes. (Little bubbles will start to surface; cover the crust if it starts to brown too much towards the end. You'll know it's done when pie only slightly jiggles in the center.) Remove from oven and cool the pie on a cooling rack at room temperature for 30 minutes.
CHILL: Cover and chill in the refrigerator for at least 1 hour.
WHIPPED CREAM: Mix the cream, sugar, and vanilla. Beat in a stand mixer or with a hand mixer until light and fluffy, and soft peaks have formed. Add to cooled lemon pie -- either spread it over the entire pie with a spatula (if the pie will be completely consumed that same day) or add it to individual pie servings. Do not add cream to the entire pie if you plan on having leftovers--the whipped cream gets watery when stored.
ENJOY: Tightly cover and refrigerate any pie leftovers. If desired, garnish slices with lemon zest, a lemon slice, and/or fresh mint. Enjoy right out of the fridge!