My now-16-month old has loved sweet potatoes since he was first experimenting with finger foods. I'd either buy the pre-cut "sweet potato fries" at costco (just cut up potatoes, no other ingredients) or just sweet potatoes whole, roast them in the oven for 40 min or more til quite soft, and give them to him in small pieces. Because they're so mushy, it's not like they require much chewing.
Another big fave around out house is little cubes of tofu. I but a brick of firm or extra firm, cut into dice-sized cubes, and simmer them in chicken broth with spices for flavor for about 20 minutes, then strain the cubes and keep in the fridge in a container. To feed him, i just microwave a small bowlful for 10 secs to get them to about room temp. he adores them.