Magic (Custard) Cake

How could I possible resist trying something calling itself "Magic Cake"? While the supposed "magic" is in how it separates itself into layers during the baking process and maintains a soft, moist center with an almost quiche-like crust, I think the real magic is in how easy it was to make and how quickly it disappeared - a 9" round disappeared in literally less than 24 hours. Twice.

• 4 eggs (separate yolks from whites) at room temperature
• 3/4 cup (150 g) sugar
• 1 stick or ½ cup (125 g) butter, melted
• 1 tsp vanilla extract
  
• 2 cups (500 ml) milk lukewarm
• ¾ cup (4 oz or 115 g) of all purpose flour
• powdered sugar for dusting cake

1. Preheat oven to 325 F degrees. Grease a 8" x 8" baking dish or a 9" cake pan (either spring-form or with removable bottom).
2. Separate eggs and beat the egg yolks with the sugar until light. Add butter and vanilla extract and continue beating for another minute or two
3. Add the flour and mix it in until fully incorporated. Slowly start adding the milk and beat until everything is well mixed together.
4. Whip the egg whites until they are stiff. Gently whisk (or fold with a spatula) the egg whites into the batter, a third at a time.
5. Pour batter into baking dish and bake for 40 to 70 minutes or until the top is lightly golden. The baking time could vary greatly depending on the oven, so take a peek at around 40 minutes and see how it looks.
6. Set on a rack to cool. If using a cake pan, after about 15 minutes, run a knife gently around the edges and then remove the cake from the pan, then allow to cool completely. 
7. Sprinkle some powdered sugar after cake has completely cooled.

Notes: My personal oven seemed to need about 50 minutes. The middle will be a little runny when it's still warm - if you let it cool completely, it should set nicely.

​I also made a "pie" version, where I pieced together some puff-pastry from the store and used it as a rough/rustic crust. This version was much more complicated in terms of timings and what needed to be done, but roughly:

1. Use a deep-dish pie pan. Lay out the crust in it, then keep it in the fridge until you're ready to fill it. Pre-heat oven to 400 F. 
2. After pouring the filling in, bake it for about 12-15 mins until the crust is to the desired golden/brown shade.
3. Turn the oven down to 325 F and bake for another 12-15 mins until the filling is the desired golden/brown shade.
4. Cover the entire "pie" with a foil cover and continue baking about 50-60 mins. To check if it's done, lift the foil cover and give the pie a light nudge or shake - the center may shiver a bit (because the filling will have a layer of cooked custard over a pocket of hot air and steam), but it shouldn't jiggle as if it's still filled with water.
5. Remove and let cool fully on a cooling rack. The center will deflate and settle as it cools.