K.L.
Popsicles are the easiest at first. Keeping her hydrated is the most important. We used Smart Water, like Gatorade w/o the sugar and color/flavor. I used it to make popscicles and jello. A couple of sips every 30 min. will help. My kids both have had their tonsils out at 3 & 4 yrs old. Keep on top of the pain meds was very important. If your meds say every 4 hrs give it on the exact hour or 15-20 min before. You don't want to get behind on the pain. Our biggest problem is that the kids were hungry. We were not limited to keep away from dairy after the first day. Soft foods that were not hot is what we were recommended.
What they ate: baby oatmeal mixed with baby fruit or added to applesauce (mixes in cold foods and fills the tummy), mashed potatoes, scrambled eggs, frozen go-gurt, ice cream, mac and cheese, smoothies made with protein powder to drink or eat with a spoon (plain yogurt, frozen fruit, juice, sweetened with honey or agave nectar, and whey protein powder)
Baby cereal was our biggest help to keep them full. You can mix it in anything that you know your kids will eat. Yogurt, pureed fruit, applesauce, etc. Warm chicken noodle soup, not hot was my son's favorite.
Hope this helps.
K.