There’s one section of Costco that I will never skip, and it’s the bakery. There’s always something that draws me over, from the sheet cakes that somehow manage to be both shockingly affordable and genuinely delicious to the constant rotation of cookies and muffins that dare me to “just try one” to the buttery croissants that disappear from my kitchen in record time. I pop in for paper towels and leave with a full dessert spread. So, being the easily tempted sweet tooth I am, I keep a close eye on new Costco bakery drops, and it debuted something recently that immediately caught my attention: Blueberry Sourdough Bread . Costco has carried sourdough from other brands before, and for the DIYers, it even sells Nordic Ware's baking starter kit . But this appears to be the first time Costco is making sourdough in-house under its Kirkland Signature label.…