Ah ok - I knew there were issues with your diet. Shame about the nuts - great way to add calories!
This is when I was eating about 4-5k a day. It did vary a lot, but it gives you an example.
Ok start off with eggs. 4 of them scrambled on some wholemeal bread or.... my favourite smoke mackerel fillets (100s of cals in these bad boys). Then for "pudding" have like Monkee suggested a multi-grain bagel peanut butter (or alternative... cottage cheese) and/or jam. Have some orange juice or some water - whichever you prefer. Maybe some granola with dairy free yoghurt. This will be at least 800 calories.
A can of tuna with some mayo. Into a couple of multi seed pittas or seeded wholemeal bread if you can make your own even better. Add some spinach or lettuce, tomatoes and maybe some cheese. Here I'd have put some nuts as well. Again well over 800 cals.
My favourite sort of meal. Smoothies!! Harder with no dairy - but you can use lactose free variants. Blueberries, raspberries, banana, oats, whey protein, peanut butter, apple, yoghurt, milk. Blended together. 1000+ calories. Yummy!
Beans and rice! Great for bulking up. Black eyed beans and a mix of wild rice and long grain brown rice. Sautee the beans (after they are cooked) with some onions, and then pour in the rice, add some chilli, and perhaps some grated cheese or stripped grilled slices of beef. Get some a wholemeal wrap and you've got a sort of burrito thing going on! Instead of shredded beef you can use chicken or whatever you want. I like cheese for adding calories and if I were to bulk as you can see.
Ok, I'm going to say it... an MRP of some kind from myprotein or BSD... OR make your own. Oats and protein powder, or hemp and or rice/soy powder. I like vanilla rice milk a LOT it's delicious and non dairy. Here I'd add peanut butter - but you can add anything else you feel would make sense. I'd also have another fruit here, banana/apple etc... Or maybe a couple of chicken breasts with some broccoli as an alternative. Again easily over 600 cals.
Fish dinner of some kind. Let's choose salmon - at least 220-250g of it - not a huge amount to be fair. Roasted sweet potato with some rosemary, and some french beans or broccoli. Add pudding - granola or a fruit, or something like that if you like something sweet.
It does take time, effort and planning. But it can be done. I personally owuld love to be "bulking" but I could literally just eat and eat. There is so much food out there you can use to bulk with. It's SO easy.