Have complex carbs, quality protein, good fat and sufficient anti-oxidants, vitamins and minerals. If you want a simple food for that provides you with all these things, then they are nuts and that too not any nuts, have a mix of sesame, almonds and walnuts every day.
even dextrose (simple sugar) falls under carbs, but avoid them and have complex carbs with sufficient fiber like oats. If you like rice, then go for brown rice instead.
Many tend to go for hydrolyzed proteins and simple amino acids like glycine, but the protein that you consume should have all essential amino acids in correct levels, that is where these nuts play a vital role, they have most of the essential amino acids, which will aid in the every type of tissue development.
And finally the fat, it is important to consume daily dosage of good fat, modern science is saying all mono and poly unsaturated fats are good. But that is not the complete truth, there are many variety of MUFA and PUFA, and the best fattty acids for our body are present in sesame and walnuts.
Have planned food everyday, you will bulk up quickly and also stay healthy without any side effects.