I make my own semi healthy mass gainers. Depending on your ingredients you will be +-1000cal
1 cup low fat ice cream, 1/2 cup milk, 1/2 cup Greek yogurt, 1/3 cup egg whites, 2 tbsp pb, 1/2 cup oats, 1/2 cut fruit, 24g whey, sometimes I throw in a handful of greens. blend on high to get the oats...