Preheat the oven (160 degrees C w/ fan).
Grease both baking tins w/ butter.
Put baking paper on the bottom of both baking tins.
Melt the butter & let it cool.
Grate the zest of the oranges & the lemons, but don't mix them!
Press out the juice of the lemons.
Mix flour, baking powder & salt.
Mix icing sugar & vanilla sugar.
Mix sugar & eggs w/ the handheld mixer until well combined.
Add molten butter & mix.
Add flour & mix.
Add cream & mix.
Pour 1/2 of the dough in another bowl & add the lemon zest. Distribute evenly w/ a spoon.
Add the orange zest to the rest of the dough & distribute evenly w/ a spoon.
Pour each flavoured dough in its own baking tin.
Bake in the oven for about 35 min.
If a wooden pin comes our clean when inserted in the cake it's fine. Otherwise add another 5 min baking time.
Let the cake in the baking tins cool down for about 10 min. Then loosen the edges of the cake from the tin (if necessary) & turn out the cake.
For the glaze mix the lemon juice w/ the sugar & bring it to a boil.
Let the glaze simmer for about 20 min until the glaze seems sticky.
Spoon the glaze over the cakes - maybe use a brush.
Let the cakes completely cool down.