my take on drizzling caramel chocolate on top of the cake

Previous post on making this yogurt cake

For below recipe, not sure it is the fact i am not using cake flour, using less oil, less sugar, or the fact the cake is left in the fridge, it felt less moist this time.

Recipe: (bake at 180 Celcius for 50-60 minutes)
120g oil (reduced from first try of 140g, should stick to 140g next time)
140g sugar (reduced from first try of 190g, i think the sugar content is just right, can increase to 150g if not sweet enough)
370g yogurt
350g flour (cake flour if possible)

Caramel Chocolate: (Adapted from Food52’s Whipped Chocolate Caramel Ganache)

50g sugar (reduce from 100g)
50g salted butter cut into tablepoon-size pieces
40g heavy cream (originally used 50g, but it flow-overed in the oven, leaving around 40g or slightly less)
30g dark chocolate (I used bittersweet)
1/2 teaspoon vanilla extract

Easy French Buttercream (recipe from Food52) Made this buttercream to top the cake some time later, not bad for me although some colleague find it very oily

2 whole large egg
Large pinch salt
63g water
133g sugar
340g unsalted butter

Whisk first 3. Then sugar
Water barely simmering, bain merie up till top of egg mixture till 175-180f (not having thermapen, i just touch the mixture making sure it is quite hot)
Strain the mixture into another mixing bowl, rapping the strainer
Beat with paddle 3-5 mins till cool and like fluffy, foam like soft whipped cream
Beat butter into foam tablespoon at a time