Wake up:- Oats + whey shake or whatever 500-600 kcal breakfast you want.(I can't eat much in the morning but can handle a shake).
Lunch time (Middle of the day, 4-5 hours after waking up):- 500-600 kcal lunch. Sounds like for you it would be a baguette. For me it's usually a pasty, sandwhiches or something.
Dinner time (8-10 hours after waking up. After school/work/before going out etc):- 900-1100 kcal meal. Usually currys and rice, pasta, pies/potato/veg, chicken or steak/potatoes or rice/veg etc.
Snacks (throughout the day, usually in the evening for me):- 300-500 kcals, bananas, apples, grapes, general fruit. Skittles, crisps, ice cream. Whatever you want to do with these kcals.
Post-work out shake: 500-600 kcals, same deal as breakfast. Have it after training or before bed on off days/if you're just gonna eat after the gym.
That's 2700-3500 kcals depending on variations on foods throughout the day. Add on your litre of milk and you're flying. As another guy suggested you can also add 2tbsp of olive oil to shakes to increase kcals pretty easily (+240 kcals across two shakes). You can't taste it and it doesn't change consistency.