I live in the Greater Cincinnati area and we have a couple bakeries that do an opera cream cake, but it is non-traditional. People get hooked on them, then they move to Akron, or Michigan, or Arizona, and ask bakers there to do an Opera cream Filling, but what they come up with isn't what they are expecting. I get brides that ask me about it all the time, and there isn't a dozen recipes for it, like all the other fillings out there, and no one can even describe what the flavor, or texture is, so I went to the BonBonerie and bought one.
First off, they sell them frozen, and they say they need refrigerated after served, but to thaw at room temp. I served it to my kids when they got home from school, and nobody was impressed. The cake its self is 3 layer of chocolate, chocolate chip, with an insubstantial whiteish filling, and was covered in chocolate ganache that had had a vague coffee flavor. Then chocolate shavings all over the sides, and 8 little decorative swirls of buttercream on top, with a little vanilla flavored diamond shaped pre-made chocolate. (I'll switch to my phone and share a picture I took)
Anyway, I tried repeatedly to taste the filling, and failed. There was just nothing to it. I tried scraping out a big bite of it and eating it by it's self, and even grabbed a piece up and licked the filling out of it! lol. One of my twins didn't like it (??? nothing not to like, but nothing to love either) so I let him leave the filling and eat the cake, and I ate it and held it in my mouth and closed my eyes....The only flavor I got was just vanilla, but it melted immediately. And that is when I realized it is nothing but flour icing! Wilton calls it French buttercream, I have heard it called Mary Kay, and Ermine, but it is just cooked sugar, milk and flour, cooled and butter and vanilla mixed in. I did a tasting today called it Opera Cream and they liked it and I got their deposit, lol. I added about 3 tablespoons of my caramel buttercream I make, just to give it a hint of flavor, and taste a bit like the Opera cream candy.
Cincinnati Style Opera Cream Filling
2/3 cup sugar
1/4 cup corn starch (or flour)
3/4 cup milk
Mix together in small pan, then cook on stove top stirring constantly, making sure to scrape the bottom as much as you can. After it gets real thick, take it off the stove and continue to stir so you don't get burned spots. Put in a metal mixing bowl, and cool to room temp, stirring occasionally. Mix in (with hand mixer)
2 sticks butter chopped in pieces
2 tsp quality vanilla
1/2 to 1 tsp caramel flavor
For home made caramel flavor, burn a 1/2 cup sugar with a tbs water in a heavy bottom pan. Stop burning it when it is deep brown, remove and put in a metal bowl to cool before it starts smoking!!! The more it is burned, the less you need, but too burned will be bitter.
For a cupcake, use double chocolate chip, cut a hole in it and dribble some chocolate coffee syrup in there, and brush some on top, fill with Opera Cream and cover top with dark chocolate ganache then with White chocolate icing. Add a decorative chunk of white chocolate, or shavings.
For the syrup, I cheated and used a 1/4 cup hot water with 2 tablespoons instant coffee crystal, and cooled it with Nestle Syrup to taste. About 1/3 cup.
I just added some white chocolate natural flavor blend from Silver Cloud Estates, then used melted white chocolate chips, spread them, froze, then crunched them up.
It was 4:30, so if anyone who has had these from Servatii or the BonBonerie wants to chime in, please feel free!
If you don't like coffee, another bakery uses raspberry. Servatii describes their Opera cream as rich...this ain't it!