Peel and core the apple, removing all seeds and skin. Cut into pieces and put into a saucepan.
Peel and core the pear. Cut into slices and add to the saucepan.
Wash raspberries and place into the saucepan along with the pear and apple. Cover with water and bring to a boil.
Simmer for about 25 minutes, or until the apple and pear are completely tender.
Put fruit into a food processor or blender. Purée until mixture is smooth, adding water, breastmilk, or formula as necessary.
Pour the purée through a cheesecloth or fine strainer to remove any seeds.