Why not try selling the eBook at a higher price, like $30?
1) Think of the $1 eBook as a minimum viable product. I hypothesized that our visitors would be willing to pay us for premium content, but I wanted to test it first. Given how few people were willing to pay $1, I decided my hypothesis was wrong. I realize that sometimes raising the price can actually increase demand, but I really doubt that's the case here.
2) I didn't know how long the traffic spike would last, so I wanted to get something out as quickly as possible. There wasn't time to create a real eBook worth $30.
Since you're not trying to game any ranking lists (e.g. Amazon bestsellers, App Store), there doesn't seem to be any reason to sell at a "bargain basement" price. A quick glance at the preview recipe shows that your ebook does have valuable content for its target audience.
As others have suggested, $9.99 or so is probably going to be a sweet spot for you. Low enough for impulse buys, high enough to make decent money.
(The only other explanation for low sales might be the plethora of free recipe websites out there. But you're selling to a captive audience that's already on your website and likes your content, so it's probably going to be less of a factor.)
I can assure you that people do not always respond more to lower prices; they'll often associate the higher price with a better item.