Place water in a pot, add steamer basket, and bring to a boil. Add quartered and separated cabbage leaves. Cover, reduce heat to medium, and cook for about 20 minutes, or until super soft.
Braise
Slice the cabbage thinly or cut into bite-sized pieces. Melt butter in a large pot over medium heat.
Add cabbage and cook, stirring, for a few minutes. Add water or broth. Bring to a boil, reduce heat to low, and simmer (covered) for 40 minutes or so, or until softened. Be sure to stir periodically.
Puree
Add sliced apple to the braising method. Cook until soft and blend in a food processor or blender. You can also stir in some breastmilk or formula.
Notes
Transfer cooked cabbage to an airtight container and keep in the refrigerator for up to 5 days.