Killer Sundae was an adorable cozy mystery. I loved the narration, & I loved the main characters & her best friendship (& not just because I'm always a sucker for strong friendships in stories!). The MC was very lovable; it was easy to see why she was such a well-loved figure in her community. The ice cream food truck aspect was really fun too :) As the story wore on, I found myself wishing that we got more focus on her career/the ice cream truck, & her friendships. I also think it was a very shallow dive into her life; I feel like somebody who has recently-ish moved back to their hometown to run a family business might have more insight on it. She mentions many characters that she knows/knew from high school & is running across, which I appreciated, but it felt a little I guess weird/shallow at times. & one thing that sort of drove me just a *tiny* bit nuts was the dialogue prompts; the author uses "said," for, like, every character, numerous times per conversation.
"We are opening an ice cream truck," I said
"I am excited to visit when you open!" She said.
I said, "I can't wait to share all of these new flavors!" 
"I can't wait to try them!" She said back. 
I'm not sure if I only noticed this because I listened to the audiobook, but it was a little bit irritating.
I also wonder if I should've read the previous 2 books from the Ice Cream Parlor Mystery series? It may have made Wyn's background more robust. I didn't realize it was a series until I was almost done! 
Overall, a very cute book, & a fun way to start off October!