After sweet potatoes didn't go down so well (he stuck out his tongue and screamed), we decided to try carrots. I bought two large carrots (for 19p/27¢-SCORE!), washed, peeled and chopped them and put them in a pot with just enough water to cover and boiled until soft, about 10 minutes.
Almost all of the cooking water will boil away, but put what's left aside. Throw the carrots into a food processor and pulse with the leftover water until blended. You can add a little bit of the cooking water at a time if you like, but I ended up using it all.
It will come out thickish, but don't worry, you'll thin it later. I put some aside for Blondie Boy's dinner tonight and put the rest into an clean ice-cube tray. Once they cooled I wrapped in plastic wrap and put in the freezer. Once they're frozen I'll pop the frozen cubes out of the tray and into a labelled freezer zip-lock bag.
When it was time for Blondie Boy's dinner I mixed the carrot puree with half a scoop of formula and water until it was the right consistency. The amount looked as though it had doubled in size and went from bright orange to a more muted coral.
He didn't gobble it down like he does with the cereal, but he certainly tolerated it more than he did the sweet potato. Although judging by this photo I think he might have preferred take-out to Mom's home cooking :)
...and just in case you were wondering I most certainly did not give my son a Chinese take-away menu to play with so I could watch Grey's Anatomy. What kind of Mother would do such a thing?