Sorry I didn’t write down what I changed. But that is more or less the one you can find here https://cookiegourmande.weebly.com/recettes-sucreacutees/buche-fuji-ramisu-de-christophe-felder (sorry that is in French :)

That is easy. Just use somethibg like this:

Kind of. I had one but ended up doing it my own way!

Nice. I was afraid the coffee taste would be too strong but it was perfect. And not too sweet so perfect after the heavy dinner!

Because it fails also

I’m French. I always do my own mayonnaise. You take one egg yolk and one small table sppon of mustard (French one, the US one tastes really differently). Mix this with a whisk. Then gradually add 250 ml of oil (sun flower for example) and whisk it at the same time. Do it really slowely. That’s all you have to do.