I have made SMBC a few times. The first two were chocolate, made with cocoa powder. They were delicious, but not very chocolatey. The next time I tried adding in melted and cooled chocolate, but there must have been a difference in temps between the SMBC and the chocolate because it looked like stracciatella gelato. Still delicious, but not the right texture. A neighborhood pastry chef invited me over to her home to learn some new skills and we needed a few frostings. One was an IMBC. When I asked how I could use melted chocolate and have better results, she and I experimented and she added the chocolate before the butter. I’ve never heard of that technique, but it worked amazingly well. Have any of you added the chocolate to the meringue before adding the butter?