First put the food on the spoon, and feed it with the spoon edge to the left (or right, your choice):
Then refill your spoon, and put the spoon in to the right (or left, depending on what you did first):
Then, refill, and put the spoon straight in:
That's it just keep repeating that! I hope it helps!
Also adding a link to Maroon Spoons - they seem to help with feeding!