Fill regular-mouth mason jar with frozen strawberries, banana, Greek yogurt, agave nectar (optional) and cranberry juice.
Remove the base of your blender's pitcher that holds the blade. Screw the base + blade, onto the top of your Mason jar. If it comes apart in pieces like mine, place the blade on top of the jar first then screw on the outer ring. (Make sure the rubber ring is in place between the glass jar and the blade to prevent leakage. Most likely the rubber ring will be stuck to the blade assembly.
Set the Mason jar now with blade assembly attached, onto the base of the blender securely. Give it a whirl until smoothie is, uh, smooth! You may need to pulse it a bit.
Unscrew the blade top from the mason jar when done. Screw on your reCap lid and you're ready to roll.
Adjust the amount of juice to adjust the thickness of your smoothie.Try different juices if you don't have cranberry juice. Grape juice, cranberry blends or anything that sounds good to you works!