Bring the cream cheese to room temperature. Dissolve the gelatin in water, then heat the bowl over boiling water.
Line the circular molds with aluminum foil, then fill with your favorite sponge cake. (The sponge cake is optional.)
Combine the cream cheese, granulated sugar, and lemon juice in a bowl, blending together over boiling hot water until smooth.
Remove the mixture from Step 3 from the hot water, then briskly stir in the yoghurt, heavy cream, then gelatin.
Fill the circular molds evenly, smooth out the surface, then chill in the refrigerator.
For the mousse, dissolve the gelatin in water, then heat the bowl over boiling water. Add the egg yolk and granulated sugar, then whisk.
Heat milk in pan, then remove from heat when it starts to boil around the edges, then add the mixture from Step 6.
Strain the mixture from Step 7 while returning it to the pan, heat over low, then remove from heat once it starts to boil around the edges.
Add the gelatin and white chocolate to the mixture from Step 8, melting the chocolate in residual heat.
Transfer the mixture from Step 9 to a bowl, then chill over ice water.
While the mixture from Step 10 is chilling, put the heavy cream in a bowl, and whip until it thickens to a yoghurt-like consistency.
Add the mixture from Step 10 to the heavy cream from Step 11, and blend evenly. (If it appears too runny, chill over iced water to thicken.)
Whisk together briskly, then pour on top of the "rare" cheesecake filling from Step 5, then chill in refrigerator until the mousse thickens. (Decorate as you like.)
This is the white chocolate that I used (Dars). One box contains 45 g.
Story Behind this Recipe
I love chocolate mousse, so thought it would taste good together with "rare" cheesecake. It took me a while to get it right, but here it is!
In Step 6, the standard method of making mousse is to whisk the egg yolk with granulated sugar until it thickens. I wanted to use the egg yolk for its coloring to create a distinction from "rare" cheesecake.