In medium saucepan whisk sugar, cornstarch, water, egg yolk, butter, lemon juice, salt, and vanilla together.
Heat over medium heat whisking until it's thick
Add strawberries and gently stir (so you don't mash the fruit)
Heat one minute.
Pour filling into baked pie shells.
Top with meringue and bake at 350 degrees for 10 minutes or until the meringue is cooked and lightly brown on edges.
Refrigerate pies once they are cooled.
Garnish with a strawberry before serving.
Alternatively, you can top the pies with fresh whipped cream, but if making them a day ahead I've found I like the meringue topping and adding fresh fruit the day of serving.