This is a children's book with illustrations! I recall it being smaller in size than the average picture book: more like the dimensions of a very thin novel.
In it, a young mouse loves the crispy top of the cheesy dinner the family shares, but rarely (or never) gets the piece he wants. He runs away, and his elder brother comes to rescue him. They are in the sewers, possibly on a raft on the water.
In it, a young mouse loves the crispy top of the cheesy dinner the family shares, but rarely (or never) gets the piece he wants. He runs away, and his elder brother comes to rescue him. They are in the sewers, possibly on a raft on the water.