Bulking up is considered when you are consuming more calories than you are burning. Depending on the diet, you may also gain a lot of unwanted fat though.
Gaining lean muscle can be done by a good diet and weight training.
As for diet, try aim to something along these lines:
Meal1
60g oats (dry weight) with water,1 scoop whey protein, handful blueberries, 125g chicken
breast + 1 whole egg
Meal 2
200g white fish, 200 butternut squash (cooked weight), 100g broccoli, 1 cup spinach,
balsamic vinegar
Meal 3
180g Chicken breast (cooked weight), 175g brown rice, 1/2 med avocado
Meal 4
180g turkey breast, 200g brown rice, 100g broccoli
Meal 5
150g Grilled Salmon (cooked weight), 50g red peppers, green salad
Meal 6
Small pot of low fat quark (250g) , 1 tbsp low cal hot choc powder + 10 almonds
or 2 scoops of 100% Scitec casein + 10 almonds
Plus
Post workout: 2 scoops whey protein, 1 banana
Otherwise if you really hate cooking, use these guys
http://www.bodyplusnutrition.com/
Buy the muscle gain meals, try eat 3 of them a day with a healthy breakfast and make sure you get a post shake after a gym session, then also have another meal in the evening depending on your macros.