Steps

1. Cut zucchini and squash into cubes. Steam. When soft, add the vegetables to blender. Purée, adding water until the consistency seems right.
2. Spread mixture into two or three ice-cube trays and place in freezer until vegetables are frozen. Remove cubes from trays and store in freezer bags in the freezer.
3. When needed, remove as many cubes as you need (usually one cube is about one ounce) and warm them up before serving.