Ashley,
You neither need nor should use a dough hook to mix croissant dough. It will get plenty of stretching as part of the lamination process. All you need is a good mix of wets and dries, then an autolysis in the fridge.
The key to making these sorts of multi-layer laminates is having the butter and dough at the same pliability and roughly the same temperatures during the roll outs and turns. Everything else, including weird flecks of butter that will ultimately left in the bowl, is way down the list.
You don't want to start with the butter too rolled out. Each roll-out should begin with the dough and butter formed into a tidy package. For successive roll-outs the package is created by the turns (aka French folds), but the first package is just dough wrapped around a block -- not a sheet -- of butter. I'm all in favor of beating, rolling and otherwise working the butter into an appropriate level of submission, but it's worth pointing out, that it must be reformed into a geometric block in order that the baker may be assured that at the first rolling, it will spread at a consistent thickness.
As I said earlier, you want the dough and butter at very similar levels of pliability and temperatures.
Moreover, neither dough nor butter can be too warm or too cold. If the butter is too cold, it will tear the dough. If too warm, it may squeeze out the sides and will certainly prevent the pastry from ever getting super flaky and light. If the dough is too warm it will be sticky, stick to itself, and prevent the butter from spreading evenly. If too cold, it will crack. All of this is a long winded way of saying the appropriate temperature is cool but warmer than right from the fridge.
Even at the first stage of working the butter -- before it's wrapped in dough -- it should be cool, but warmer than fridge temp; and should certainly not be frozen.
BDL
