Puree or mash 1 cup strawberries in food processor or by hand.
Combine sugar and corn starch in a medium saucepan. Gradually stir in water, mashed strawberries, lemon juice and food color (optional). Stirring constantly, bring to boil over medium heat and boil 1 minute. Let mixture cool slightly.
Gently stir remaining 3 cups sliced strawberries into cooled filling. Spoon into pie crust. Refrigerate at least 2 hours, just until set.
Pie is best served the same day prepared. Top with whipped cream, if desired.