I remember that you used to be able to pound a jar of nut butter - have you tried a nut-based, grain-free granola as your breakfast? You could chop up dried fruit and dark chocolate to make it even tastier - it's absolutely moreish! MY partner's not often hungry in the morning, but he'll still sit down to a big bowl of my Nola because he loves the taste so much. For that reason, I don't let myself touch the stuff ;)
A mate of mine is currently a skinny little slip of a guy, and he's doing everything he can to bulk up. He's eating six times a day, and training like a maniac. Like you, he never used to have much of an appetite, and while I don't agree with what he's consuming - lots of processed protein powders, of course - it makes sense to take some extra calories in liquid form if you can handle it. I love cream with cinnamon & ground vanilla as a rich dessert.
Find the flavours and aromas that make you drool, and use them as much as possible. I love the smell of roasts in the oven, fresh basil, and bacon, and the flavours of salty butter, runny egg yolks, and wilted greens. I've just spent months battling a drug-fueled, uncontrollable appetite so I avoided those stimuli outside of my eating window. Perhaps you can use the opposite to your advantage.