I would use a blender and add something to thicken in up, otherwise the oatmeal tends to fall to the bottom. Or just stir or shake before drinking if you don't down it all at once. My morning shake:
1/2 Cup Oatmeal
2 1/2 Tablespoons Golden Flax Meal
1 Scoop ON 100% Whey
1/2 Cup Cottage Cheese
8 Oz of Milk, Skim or 1% usually.
Breaks down roughly to 53 grams of carbs, 53 grams of protein and 17 grams of fat with the 1% milk used.