Preheat oven to 350ºF. Combine graham cracker crumbs, brown sugar, and melted butter in a medium bowl. Press mixture into the bottom of a 9-inch pie dish and bake for 8-10 minutes. Remove from oven and allow to cool.

Lower oven temperature to 325ºF. In a medium bowl, whisk the sweetened condensed milk, egg yolks, lime juice, lime zest, and salt together until smooth. Pour the filling into the cooled crust and transfer to the oven. Bake for 25 to 30 minutes, or until set around the edges and slightly jiggly in the center. Let cool at room temperature for about 15 minutes before transferring to the refrigerator until cold and firm, about 3 hours.

In a saucepan, add the strawberries and sugar. Bring to a simmer over medium heat, stirring constantly. Once strawberries have begun to soften, use a potato masher to smash the berries to desired consistency. Combine the cornstarch and water in a small bowl, then pour into saucepan. Continue stirring until sauce has thickened. Transfer sauce to another bowl to cool completely.

In the bowl of a stand mixer fitted with the whisk attachment, beat the cream cheese, sugar, and vanilla together until creamy, about 2 minutes, scraping down the sides of the bowl as needed.

With mixer on low speed, slowly pour the heavy cream into the bowl. Once all heavy cream has been added, increase the speed to high, and whip until stiff peaks form, about 2-3 minutes, scraping down the sides of the bowl as needed.

Spread topping evenly on top of the cooled key lime filling. Top with the strawberry sauce*. Chill at least 5 hours or overnight before serving. Decorate with whipped cream, if desired.