In a medium bowl, combine 2 cups sliced strawberries, 1 tablespoon lemon juice, and 1/4 cup powdered sugar; stir and let sit for 10 minutes to release juices.

In a large bowl, beat 1 cup heavy whipping cream with remaining 1/4 cup powdered sugar and 1 teaspoon vanilla extract using a whisk or electric mixer until soft peaks form, about 2-3 minutes.

In a small saucepan, whisk 2 tablespoons cornstarch into 1/2 cup strawberry juice over medium heat; cook, stirring constantly, until thickened, about 5 minutes.

Remove the saucepan from heat and fold in the macerated strawberry mixture until fully combined.

Gently fold the whipped cream into the strawberry pudding base until no streaks remain.

Pour the filling into the pre-baked and cooled pie crust, smoothing the top with a spatula.

Cover the pie with plastic wrap and refrigerate for at least 2 hours until set before serving.