Put cottage cheese in blender with a small splash of water and blend until it is smooth, creamy and no longer grainy (look closely) - about 2 minutes. (Note 1)
Add plain yogurt to blender and blend for 30 seconds to liquify.
Soak frozen strawberries for a moment in a bowl of hot water to soften, add to blender and puree.
Add bananas and orange juice concentrate and blend to combine. Scrape down sides of blender with a spatula.
If mixture is too thick add a splash of water to thin it out to desired consistency (Note2)
Notes
Note 1: In my experience it takes a couple of minutes to get the cottage cheese completely smooth and all the graininess gone, but it's worth it for the texture of the end result.Note 2: Adding a splash of water shouldn't water down the flavor of the smoothie, because of the orange juice concentrate. If you accidentally add too much water and find the taste suffers, add a bit more orange juice concentrate to balance it out.