Jesus and I by Aloysius J. Heeg, S.J.
I started this year using this book in addition to Our Heavenly Father (Faith and Life 1) with First Daughter, but early in the year dropped our Faith and Life readings and focused only on this book. I thought Jesus and I covered new material for her in a way that worked perfectly in a Charlotte Mason environment and she was hearing the most important parts of the Faith and Life book at her CCD class.
The short chapters, often just a few paragraphs, follow the Baltimore Catechism and present all the important information for First Communicants and those preparing for First Reconciliation. A simple narration after the reading would be perfect, but there are questions provided for those who are uncomfortable with child-led narration or who want to be sure the child has mastered all of the information. A few sections at the back combine the information from earlier chapters into a single space for "When I Go to Confession" and "When I Go to Holy Communion" as well as a section of review questions for First Communion.
I originally expected this to be a small simple little catechism and therefore thought it would be fine to do this year in first grade even though we weren't preparing for First Communion yet. It's certainly gentle enough for a first graders (and yet complete enough for much older students as well), but it's absolutely perfect for First Communion preparation and I almost wish we'd saved it for next year. It's small and inexpensive, too, which only make it better.
For most of the year, we read this book together once a week. Each lesson probably took about five minutes including both the reading and the narration, though we had some interesting conversations about venial and mortal sins that extended the time of those lessons. After we finished Clare's Costly Cookie, we replaced that reading with an additional one from this book, so we finished in less than 30 weeks.
I highly recommend this book for First Communion Preparation and think it could replace any other catechism during that year (though you may want to have other times for Scripture study, saints stories, and celebrating the liturgical year).
I purchased this book at Sacred Heart Books and Gifts (linked above directly to the book). The owner very kindly began carrying it after I asked her if she would consider adding it to her store. She did and I'm so very grateful! (I receive nothing if you purchase this or anything else at Sacred Heart.)