“Bird’s milk” cake, a.k.a. “ptasie mleczko” cake, a.k.a. торт “Птичье молоко”, is a very popular dessert in Russia. (In its original, candy, form, it is also well-known in Poland and elsewhere in Eastern Europe.)
Contents
Overview
“Bird’s milk” cake consists of a sturdy cake base, surmounted with a thick layer of agar-stabilized egg white mousse, topped with a dark chocolate glaze.
The recipe consists of baking the cake; placing the cooled cake layer on the bottom of a deep springform pan, then pouring the warm mousse on top of the cake base; and finally, once the mousse has cooled and congealed, pouring the warm chocolate glaze on top of the mousse. The cake sits in the refrigerator while the glaze hardens; at that point, it is ready to slice, serve, and eat. The entire process may take up to 6 hours, though at least 4 hours of that is spent waiting for various components of the cake to cool.
This is not a beginner-level recipe! If you do not have a decent grasp of how to work with egg foams and sugar syrups, do not attempt to make this cake.
Equipment
- 9″ cake pan, at least least 2″ tall
- 9″ springform pan, at least 3″ tall (if using a shorter pan, line the walls with a strip of poster board, heavy sketch paper, or a similarly stiff stock)
- Electric mixer (stand mixer preferred, though a good hand mixer suffices)
- Mixing bowls (enameled or stainless steel, not plastic or glass)
- Parchment paper
- Saucepans, spatulas, whisks, etc.
Ingredients (shopping list)
One standard package of each of these ingredients will suffice.
- Agar
- Baking powder
- Butter
- Cocoa powder (Dutch-process)
- Corn oil (or similar)
- Cream of tartar
- Eggs (extra-large)
- Flour (all-purpose)
- Greek yogurt (full-fat, plain)
- Half-and-half
- Lemon juice (or vinegar)
- Salt
- Sugar (granulated)
- Sweetened condensed milk
- Vanilla extract
Cake base
Though the cake base recipe given here is well-tested, any relatively sturdy chocolate-flavored cake base will work, such as a buttermilk chocolate cake, etc. (But don’t try substituting a light sponge cake; it will not properly complement the texture of the mousse.)
A good full-fat sour cream may be substituted for the Greek yogurt; canola, vegetable, or coconut oil may be used in place of corn oil.
Ingredients
Dry (A)
- 1 cup minus 2 tbsp all-purpose flour
- 1⁄4 cup Dutch-process cocoa
- 3⁄4 cup granulated sugar
- 2 tsp baking powder
- pinch salt
Wet (B)
- 1 extra-large egg
- 1⁄4 cup half-and-half
- 1⁄4 cup sweetened condensed milk
- 1⁄3 cup full-fat plain Greek yogurt
- 3 tablespoons corn oil (or similar)
- 1 tablespoon vanilla extract
Instructions
- Preheat oven to 350°F.
- Grease 9″ round pan with butter; line bottom of pan with parchment paper.
- In a large bowl, whisk together dry cake ingredients (A).
- In a large measuring cup or separate small bowl, whisk together wet cake ingredients (B).
- Add (B) to (A); mix with spatula until combined.
- Turn batter out into prepared pan.
- Bake.
(Approximately 30 minutes pass)
- Cool cake in pan.
(Approximately 10 minutes pass)
- Turn cake out onto wire rack.
- Let cool while you proceed with next part of recipe.
Mousse
The agar-stabilized mousse will set up very quickly once it’s mixed; do not let the mousse stand even for a minute before pouring it onto the prepared cake base!
Ingredients
(C)
- 200 g butter
- 100 g sweetened condensed milk
- 2 tsp vanilla extract
(D)
- 150 ml water
- 8 g agar
(E)
- 250 g sugar
(F)
- 6 large egg whites
- 1⁄2 tsp cream of tartar
Instructions
Preparation
- Take 200 g butter and 100 g sweetened condensed milk (C) out of fridge.
- Cut butter into 1⁄2″ pieces; let stand to soften.
- In medium saucepan, mix 8 g agar with 150 ml water (D); let stand.
- Separate 6 eggs (F). Cover egg whites and let stand. (Reserve egg yolks for future use.)
(Approximately 1 hour passes)
- Line base of springform pan with aluminum foil; grease sides with butter (or line with baking paper).
- Place cooled cake round into springform pan. Cover pan with towel or plastic wrap.
Action
- Using beater attachments of electric mixer, cream the butter, sweetened condensed milk, and 2 tsp vanilla extract (C) in a medium mixing bowl. Set aside.
- Wipe down the inside of a deep mixing bowl with a squirt of lemon juice or vinegar.
- Place the egg whites and 1⁄2 tsp cream of tartar (F) into wiped-down deep mixing bowl. Set aside.
- Heat the agar & water (D) on medium heat until it begins to boil.
- Add the 250 g sugar (E) to saucepan; whisk to combine.
- Continue heating, swirling the mix occasionally, until an instant-read thermometer shows 220°F / 110°C. Take saucepan off heat.
- Using whisk attachments of electric mixer, beat egg whites until they form a soft foam.
- While continuing to beat egg whites with mixer, pour the agar/water/sugar syrup into the whites in a thin, steady stream. (Foam will increase in volume and become glossy.)
- Add the beaten butter mix to egg white foam, while continuing to beat with mixer. (Foam will deflate somewhat and become more liquid.)
- Once butter is fully incorporated, pour the mousse into the springform pan, on top of the cake base.
- Let stand, at room temperature, until congealed.
(Approximately 2 hours pass)
Chocolate glaze
Depending on the brand of chocolate, and your preferences, the amount of sweetened condensed milk may be adjusted, to make the glaze sweeter or more bitter. It shouldn’t be too sweet, though; the bitter flavor of the chocolate should offset the mild, sweet taste of the mousse.
Ingredients
- 100 g bittersweet (a.k.a. 70% dark) chocolate
- 75 g butter
- 20 g sweetened condensed milk
Instructions
- In small saucepan, melt the 100 g butter with the 20 g sweetened condensed milk.
- Take saucepan off heat and add the 75 g dark chocolate. Cover and let stand.
(Approximately 10 minutes pass)
- Whisk melted chocolate with the melted butter until smooth.
- Let stand until cooled almost to room temperature.
(Approximately 20 minutes pass)
- Pour chocolate topping on top of fully-congealed mousse.
- Use spatula to make sure mousse is fully covered with an even layer of chocolate.
- Gently but quickly rotate pan back and forth, to ensure a smooth and flat surface.
- Place cake into refrigerator until chocolate solidifies.
