Cream Egg Brownies really rich

Thanks to Felila for linking the perfect brownie base for my cream egg Easter brownies in another thread.  I'm still tweaking these and have had a couple of tries.  I used 85% cocoa chocolate, I couldn't get unsweetened, and reduced the added sugar to 180g.  This makes the perfect base.  There wasn't enough of the creme egg filling on this version so am going to double for next time.

The problem at the mo is that these are SOOO RICH.  The sweetness is perfect as not too much but still really rich.  The recipe is below but what could I tweak to perhaps cut the richness a bit without losing the creme egg top.  I was thinking of subbing the chocolate in the brownie base for cocoa but not sure if that would work or how to do it?

Brownie Base

85g 85% chocolate
115g unsalted butter
180g granulated sugar
2 eggs
1 tsp vanilla ext
1/4 tsp salt
85g plain flour

Cream Egg Filling

120ml light corn syrup
56g unsalted butter
1 tsp vanilla ext
1/4 tsp salt
3 cups icing sugar

Choc Top

100g 85% chocolate
100g 90% chocolate
1 tbsp unsalted butter