Does this book description sound familiar?

[gothicromancereader]

I'm looking for the name/author of a gothic that I owned years ago and got rid of (shame on me). All I remember is that the main character was a governess named Allegra. Her charge was an adorable little boy, whom Allegra adored. The little boy had a dog that was his faithful companion, named Top O' the Morning. The boy's mother was Marianne, who was actually the villain of this novel.
The books ends when Marianne sets fire to the family mansion and Allegra is almost prostrate with grief thinking that her charge is still in the house. Thankfully, he is not, and Allegra and her love interest adopt the boy.

Does this ring a bell with anyone? Thanks in advance!

Solved! Night Falls too Soon - Francesca Chimenti