Making the Berry Sauce

1. In a medium saucepan, combine frozen strawberries, sugar, and water over medium heat. Stir occasionally and bring to a simmer.
2. Cook for 8-10 minutes until the strawberries become soft and start to break down.
3. Use an immersion blender to puree the mixture until smooth. If using a standard blender, allow the mixture to cool slightly before blending and return it to the pan afterward.
4. In a small bowl, whisk together the heavy cream and cornstarch until no lumps remain.
5. Slowly pour the cream mixture into the strawberry sauce while whisking constantly.
6. Continue to cook for 2 more minutes, stirring continuously, until the sauce thickens slightly.
7. Remove from heat and transfer to a heatproof bowl. Let the sauce cool completely before using. If needed, refrigerate to speed up the cooling process.

Assembling the Ice Cream Cake

1. Remove the strawberry ice cream from the freezer 30-40 minutes before assembling to allow it to soften slightly.
2. Line a 9-inch springform pan with parchment paper to prevent sticking.
3. In a medium bowl, mix vanilla cookie crumbs with melted butter until evenly moistened.
4. Press half of the crumb mixture firmly into the bottom of the prepared pan to form the crust.
5. Gently spread half of the softened ice cream over the crust in an even layer. If the ice cream becomes too soft, return the pan to the freezer for 15 minutes before continuing.
6. Drizzle half of the cooled strawberry sauce over the ice cream layer. Use a knife to create gentle swirls if desired.
7. Sprinkle the remaining cookie crumbs over the sauce, pressing them down lightly.
8. Spread the remaining ice cream over the cookie layer, smoothing it evenly.
9. Drizzle the rest of the strawberry sauce on top, creating a decorative swirl.
10. Cover the cake with plastic wrap (without touching the surface) and freeze for at least 8 hours or overnight until completely firm.