Step 1Heat the oven to 375 degrees. Clarify the butter by melting it in a small skillet over medium heat. Do not let it brown. Remove it from the heat, set aside for 5 minutes. Skim the foam, pour off the clear yellowish liquid and reserve.
Step 2Beat the sugar and eggs in an electric mixer for 1 minute.
Step 3Place the bowl over simmering water in a large saucepan and beat the mixture with a hand-held mixer at high speed until it's light and foamy and reaches a temperature of 104 degrees, about 1 1/2 minutes. Remove from the heat and beat about 5 minutes, until light and fluffy. Then reduce the speed of the mixer and beat (with mixer or by hand) for another 5 minutes, until the mixture has cooled and reached a ribbon consistency.
Step 4Sift in the flour; fold it gently into the mixture with a spatula. Don't overwork. Fold in the clarified butter.
Step 5Pour the mixture into a 9-inch greased and lightly floured springform pan. Bake 25 to 30 minutes. Cool in the pan or on a wire rack.
Step 1Combine the sugar, water and kirsch in a small saucepan. Bring to a boil over medium heat. Reduce the heat and simmer for 5 minutes. Allow the syrup to cool.
Step 2Clean and stem the strawberries; pat dry. Slice vertically into pieces about one-half inch wide. When the syrup is cool, pour it over the berry slices. Allow to macerate for one-half hour.
Step 1Pour the water into a small saucepan and add the sugar. Bring to a boil over medium heat. Wash down the inside of the pan with a pastry brush dipped in cold water. Check the temperature with a candy thermometer.
Step 2When the mixture reaches 230 degrees, place the egg whites in the bowl of an electric mixer and beat, using the whisk attachment, until stiff but not dry. Keep an eye on the sugar mixture and stop cooking as soon as it reaches 238 to 240 degrees, about 15 minutes.
Step 3When the egg whites are stiff, reduce the mixer speed to low and pour in the cooked sugar mixture in a thin, steady stream, keeping it clear of the beaters. Beat at medium-low speed for about 15 minutes, until tepid (about 86 degrees). Let stand until cool.
Step 4Add the butter to the cooled meringue, a little at a time, while beating at medium-high speed for 5 minutes until the buttercream is smooth and homogeneous. May be stored in the refrigerator for several days in an air-tight container. Makes 3 cups.
Step 5Remove the cake to a serving platter. Score the cake around the top, 1 1/4 inches from the edge and hollow out the center to a depth of 1 inch. Save cake pieces for another time.
Step 6Brush some of the syrup from the berries into the hollowed out portion of the cake. Use a slotted spoon to spoon the berries into the hollow. Top with dollops of buttercream. Serve the remaining buttercream in a bowl and spoon remaining syrup over the cake as it is served.