Separate egg whites from yolks. In a medium bowl, whisk together yolks, sugar, and vanilla. Add flour until well blended.
In a large bowl, beat egg whites on high-speed until they foam and are about 3-4 times in volume (about 2 1/2 to 3 minutes). Don’t beat too long or they will become too stiff and won't blend well.
Use a spatula to gently fold the yolk mixture into the egg whites until well combined. Don’t mix too much or you will lose volume. The batter should have a fluffy texture.
Divide the batter evenly among the two lined cake pans & bake for 20 minutes until the tops are golden.
As soon as the cake is done, turn the cake out onto a clean surface and peel off the wax paper. This is much easier to do while the cake is still very warm.
Use a knife to remove rough edges. Let cakes cool to room temperature.
Place one of the cake layers into the bottom of a springform pan and pour 1/2 of your soda over the cake and let it soak in.
In a small saucepan, combine gelatin with milk. Whisk together over medium heat. Continue whisking until it just begins to steam, then remove from heat (DON'T BOIL). Set aside to cool.
In the bowl of an electric mixer on medium speed whisk together sugar, sour cream, and cool whip until well blended.
With the mixer on, slowly add the warm milk mixture. Immediately pour over the first biskvit layer inside the prepared baking dish. Smooth the top as evenly as possible. Cover and refrigerate to cool.
Freeze your mixing bowl and whisk attachment for 10-15 minutes before beating the heavy cream and keep it refrigerated until you are ready to use it.
Whip the heavy cream at high speed until it forms soft peaks (1 minute).
Add the sifted powdered sugar and vanilla and continue whipping at high speed until the cream forms stiff peaks but is still smooth (about 1 minute).
Place the second cake layer over the ptichye moloko and pour the rest of syrup/soda over the cake layer. Cut around the edges of the cake to loosen it from the springform pan.
Trim the edges of the ptichye moloko to make it even with the cake layers.
Frost the cake and even it out with a food-scraper.
In a small saucepan, over low heat, melt chocolate chips, stirring constantly until smooth.
Transfer to a ziploc bag and cut a small hole on the tip. Practice a couple of strips on wax paper. Transfer the cake to your favorite cake stand. Refrigerate the cake until ready to serve.