There is not much that you can do about food drying out, aside from ensuring that the veggies are as fresh as possible and to begin with a fair amount of food in the plate. Generally speaking, a pile of veggies will stay moist/fresh longer than scattered veggies.
Though it may be true that **some** uros eat as litle as you say, 1-2 tbsp does not sound generally like an appropriate amount of food, except for perhaps youngsters. Besides, you would not want to offer only as little as you think they might eat but rather stimulate their willingness to feed by offering more varied choices and quantities.
My uros seems to prefer feeding in the bright, so if you move the food far away from the main basking area, it would be best if you have a full-spectrum light near the feeding site (this is a good thing to have anyways).
Good luck.
-Felix