Here is a high calorie shake that I like to make:
2 scoops whey protein powder
3 cups milk
1 cup oats
2 tablespoons natural peanut butter
Just throw it all in a blender and then drink. Comes out to just over 1000 calories, and isn't even very filling. If you aren't gaining weight then you aren't eating enough. If you are really serious about this, go to
fitday and start tracking what you eat every day. If after a month you haven't gained any weight, add about 300 cals to your daily total, then lift for another month and reevaluate. You might be surprised how little you are actually eating if you keep track. I used to think I was incapable of gaining weight and was eating "everything" and once I wrote it all down it barely came out to 2000 calories. Now I have to eat 4400 cals per day to keep making progress.
Another good site to go to for information is
wannabebig forums