Preheat the oven to 350 degrees F. Spray a 9-inch pie plate with nonstick spray liberally. Or brush it with melted butter!
In a bowl, whisk together the sugar, flour and salt.
In another bowl, whisk together the egg yolks and melted butter. Whisk in the milk, lemon juice, almond extract and lemon zest until combined. Stir in the dry ingredients.
Beat the egg whites in the bowl of your electric mixer until stiff peaks form. Slowly fold the egg whites into the lemon mixture, gently, until combined. Pour the batter into the pie plate.
Bake for 30 to 35 minutes, until set. Top with sliced almonds and serve.