Finely crush the saltine crackers (but not to dust) and place in a large bowl with 1/2 cup sugar. Cut in the butter until the crumbs hold together like dough. Press into an 8-inch pie pan and chill for 15 minutes
Bake the pie for 18 minutes, or until the crust is golden brown. Remove from oven to cool on a wire rack.
Using a hand mixer, mix the egg yolks and milk together until completed combined. Add the citrus juice and mix again until completely combined.
Pour the mixture into the pie crust. Return to the oven and bake for 16 minutes, or until the filling has set.
Cool completely, then refrigerate for 2-3 hours before slicing. Serve with fresh whipped cream and garnish with a sprinkling of sea salt.