Oils, butter, dairy, rendered fat, cheese, mayo, nuts, seeds. All those are calorie dense. You could easily turn a salad into something that packs over 600 calories with not a lot of effort. Even a smoothie can pack a wallop.
Eating more calories isn’t going to help you lost weight any better than fewer calories. But if you want to eat more I’d simply add fat and cut back on the salad a bit (or drench it in olive oil and/or make it with fatty cheese).If you’re still struggling I would add some quality carbs, like sweet potatoes and put butter in them.
> I’m worried i won’t lose weight if I’m not eating enough calories.
That’s the opposite of how it works. The fewer calories you consume, the more weight you will lose. Your metabolism will not adapt such that eating more calories will cause you to lose more weight or that eating fewer calories will cause you to lose less weight.
Going straight to OMAD might be tough. You might be better off to go with two meals per day for now. I worked up to OMAD. A single meal felt like far too much food initially, but now it feels normal.
When you are minimizing carbs, make sure to eat a generous amount of proteins, then add fat as needed. Keep in mind some of that fat is coming from the 35kg of fat you want to lose.
Maybe go for meat with a bit more fat in it. Cook the meat in butter. Add some cheese.