jjonewell, Have some tips for you. I just fed my toddler Apple Cobbler.
I used the eviscerator 235X food processor and tried a few others and they worked
Clicked on the processor and had my sim make a group meal either using serve lunch or serve desert.
With the toddler in the highchair click on the highchair either the tray or the leg. That will bring up the option to Serve Food. You will be able to select any group meal your sim has prepared.

It's been awhile since I use the processor...too busy with too many kids I guess. I forgot to mention: Sometimes when you click on the highchair even though you have the group meal good ole' Mommy will go the the food processor to make a fresh batch. An be prepared, sometimes the toddler with throw the entire meal on the floor, lol.

...but you do need to have a "group" meal prepared before you can give/make it for the toddler.

The only time I have seen toddlers throw the food on the floor is when they have already eaten because another sim game them a bottle or some gruel. It really drives me crazy when the toddler has already eaten but is still in the high chair and one of the teen or older sims will go make a meal which just ends up wasting food since they toss it on the floor.

And I usually don't even try having my sims make baby food out of the meals in the frig unless there are no babysitters or butlers on the lot who always rush over to feed the toddler, and even then you still have to keep an eye on any of the other members of the household who are capable of feeding the kid or your sim is going to spend a lot of time cleaning the goop off of the high chair.

And here I always thought the food thrown on the floor thing was indicative of a future food critic in the making. These are the sims to whom I threaten to serve baby bottles and bowls of gruel when they become teens and have their friends over for parties and dinner.