In a medium saucepan, combine the sugar, cornstarch, flour and salt. Gradually stir in the milk. Stir constantly over medium heat until the mixture comes to a boil. Reduce heat and continue to cook, stirring, until thickened.
In a small bowl temper the egg by adding a couple tablespoons of the hot custard mixture into it, whisking briskly until thoroughly combined. Stir the egg mixture back into the saucepan. Stir and heat until just boiling. Remove from the heat and allow to cool. Once cooled, put in the refrigerator to chill thoroughly.
Once chilled, beat the mixture with a whisk or electric beater until smooth. Then, use a spatula to gently fold in the whipped cream and vanilla.
Spread the toasted almonds (if using) over the bottom of the baked pie crust. Spoon the prepared cream filling and spread evenly.
Halve 3 cups of the strawberries and place over the cream layer.
Crush the remaining half cup of strawberries and combine with water in a small saucepan. Bring to a simmer over medium heat for 2 minutes. Strain the mixture, reserving the juice.
In a separate bowl, mix sugar and cornstarch. Gradually stir in the warm juice. Return to the saucepan and cook, stirring, until the mixture is thick and clear. Add food coloring if using. Cool slightly.
Pour the glaze over the strawberries in the pie. Refrigerated for 2-3 hours before serving.
Serve chilled topped with additional whipped cream if desired. Enjoy!