Preheat oven to 350 degrees Fahrenheit. In a food processor fitted with the knife blade, pulse all the tea biscuits into crumbs. Add melted butter and mix.
Divide crumbs between two springform pans (I use two 9-inch pans) and press down to form an even crust.
Bake for 10 minutes. Set aside.
Combine all ingredients in the bowl of an electric mixer with the whisk attachment. Mix until smooth and no lumps are visible, stopping to scrape down sides if needed.
Divide cheese batter between the two pans. Bake for 45 minutes.
Turn oven off (do not open) and leave cakes inside to cool for at least 4 hours. (I baked the cakes right before going to sleep and let them cool in the oven overnight.)
Combine all ingredients in the bowl of an electric mixer fitted with the whisk attachment. Beat for 2 minutes until creamy but still a bit runny. Spread over both cakes, smoothing the tops with an offset spatula. Freeze.
To remove the cake from the pan, first run a sharp knife around the cake. Let cake thaw before serving.
Yield: 2 (9-inch) cakes. Feel free to halve the recipe.