Maple "Butter" Bars

I've been testing out recipes that me and my nephew (with specific allergies) can enjoy together and this one from Flying Apron's Gluten-Free & Vegan Baking Book caught my eye. It's supposed to be like shortbread which I love. I really wish this book had more pictures of their recipes, so I knew if these look right.  Since I don't have a mixer, I mixed it by hand with a strong fork and I'm wondering if that changes the composition a lot.  I also used a 9x13 pan instead of the 9x12 pan, so I think they're thinner than they're supposed to be:

They are tasty and not overwhelmingly sweet and I certainly enjoy them, but they seem very dense and chewy, rather than crisp which I associate shortbread with.  Also, when I pulled the pan out of the oven, the coconut oil had bloomed to the top and was just sizzling/boiling when I pulled the pan out of the oven, though it eventually settled back down into the cookies as it cooled. Also, the recipe advised to score the cookies while they're hot, but I found this unnecessary and was able to cut them into bars pretty easily.  Hmm, maybe I need to try this out with a mixer sometime and see if it changes things.  Anyone familiar with this recipe and can tell me if I made these right? 

Anyhoo, if you'd like to try making these (it's pretty easy with 5 ingredients)--please let me know how they turned out (especially if you've got a stand-up mixer)!

Maple "Butter" Bars

- Preheat oven to 375 degrees
- Combine 2 3/4 c of brown rice flour and 1/2 tsp salt in a medium bowl.
- In the bowl of a stand-up mixer fixed with paddle attachment, combine 1 c coconut oil (or palm oil), 1 c maple syrup, and 1 tsp vanilla until well mixed. With mixer on low speed, add flour mixture a little at a time until well mixed, about 3 minutes.
- Spread batter evenly into a parchment-lined 9x12 pan. Bake until edges harden slightly, about 15 minutes. While dough is hot, score it into 12 pieces with a knife. After it has cooled, slice it the rest of the way through and remove bars from pan.