Sorry to resurrect this old thread, but I have to dedicate my very first post ever on CC to Gretchen's SMBC. It's amazing and I find it very easy to follow and adapt flavours.
If you find it too sweet, add less powdered sugar (I usually use somewhere around 60g) but it's also amaaaaazing if you fold in melted chocolate at the end. Goodness, just fudgey and yum yum yum. I also use all butter as well. Sometimes maybe up to 50g shortening, but that's it. With all butter, there's no problem with stability.
Also just tried her pastry cream recipe and it came out perfect.
For cakes, I like the Brown Eyed Baker. Although the recipes are sometimes very complicated, they yield a very nice, high quality cake, in my experience. Especially the dark chocolate cupcakes... delicious.