Preheat the oven to 180 degrees Celsius/ 350 degrees Fahrenheit. Butter a 26 cm diameter/ 10 inch springform. Cut a circle and a long stripe of baking paper to fit the bottom and the sides of the pan and cover the springform pan with them.
Melt the butter in a small pan and leave to cool down until ready to use.
Separate 4 eggs. Beat the egg whites until stiff and set aside.
Beat the egg yolks and the remaining whole egg with the sugar until pale and creamy.
Add the flour, stir gently to incorporate, then add the egg whites and finish by adding the melted butter.
Pour the batter into the springform and bake for about 30 minutes until a skewer inserted in the middle of the cake comes out clean. Leave to cool in the pan for about 10 minutes, remove from the pan and leave to cool completely on a wire rack.
When cool, slice the cake in two.
Soak the gelatin leaves in cold water for about 10 minutes or according to the packet's instructions.
In the meanwhile blend 100g/ 3.5 oz strawberries. Add the cream cheese, yogurt, sugar, and vanilla sugar and mix everything well together.
Beat the heavy cream until stiff and set aside.
Chop another 100 g/ 3.5 oz strawberries into small pieces and set aside.
Squeeze the gelatin leaves gently to remove the excess water. Place in a pan large enough to hold the whole filling afterward and heat gently until completely dissolved. Do not overheat the gelatin, it shouldn't start to boil at all.
Take away from the heat and start incorporating the cream cheese mixture one tablespoon at a time. Only add the next tablespoon of filling when the previous one is completely incorporated. Proceed until all the filling is incorporated.
Add the chopped strawberries and mix in very gently.
Wait for a couple of minutes until the filling starts to set. In this case, the filling will start setting quickly so it is better to have the heavy cream ready to use. Fold in the stiff heavy cream gently.
Assemble the cake:
Place one cake slice on a platter. Set a metal cake ring around it and fit it carefully.
Pour the filling inside the ring, place the second slice of cake on top, and press gently.
Slice the remaining strawberries. Place on top of the cake to get a nice pattern.
Prepare the fruit tart glaze powder according to the packet's instructions or as following: Place the fruit tart glaze powder in a small pan and mix with the sugar. Add 250 ml/ 1 cup cold water little by little while stirring to avoid getting clumps.
Bring to a boil while stirring continuously, remove from the heat, let cool down for 1 minute, and spoon over the strawberries starting in the middle and going slowly around to cover all the strawberries.
If making your own glaze, see the note.
Place the cake in the fridge overnight. Shortly before serving, remove the ring.
Toast the almond slices in a pan without using fat and shaking the pan often to avoid burning the almonds. Transfer to a plate and let cool completely.
Whip the heavy cream until stiff. Spread the cream around the edge of the cake and coat it with the almonds.
How to make cake glaze?
Whisk together 250 ml/ 1 cup water or a mixture of clear (or red) fruit juice and water with 1 tablespoon lemon juice, 2 tablespoons potato starch, and 1 tablespoon granulated sugar. The mixture should be completely smooth.
Bring to a boil stirring continuously.
Let bubble once, the mixture should be clear now.
Let cool for one minute and use to glaze the strawberries on the cake.