I agree. The first to go would be the butter and the fat in the nuts going rancid. How long can you keep butter? Being mixed up it probably wouldn't last as long as a block of butter, but if it's airtight it should last at least a week, probably longer. Because you don't know what bacteria might be in it just from mixing and packing, it's important not to sample it raw. Bake it up when you can, and freeze the extra cookies if you can find the space.

Leavening/soda makes dough rise. Proving/proofing shows that the yeast is alive (not an issue with dry granulated yeast, but absolutely necessary for cake yeast and starters). Rising is what the dough does. Commercial bakers nowadays proof yeast in the dough while it rises because the yeast is so reliably alive that they skip the step where you feed the yeast and make sure it bubbles up before wasting a batch of flour on it, which is the original meaning of proofing your yeast. They just look at the risen shaped loaves to see the proof. This has become so prevalent that bakers are using the word proof and rise interchangeably. You raise your hand and your crops, and rear your children. :)

"I am going to try freezing shortbread and oatmeal raisin. I read that they work well." No problem at all; I do it all the time. I freeze most cookie doughs with great results, including shortbread, sugar cookie and any type of oatmeal or other drop cookie doughs. Right now I have a lot of cookie dough in the freezer, including shortbread, sugar cookie, oatmeal/cranberry, gingerbread and molasses. What I wouldn't freeze are more delicate cookie doughs that have more liquid and are thinner, such as florentines and tuiles. Sooz, freeze away! I agree with plllog. Snickerdoodle dough freezes beautifully but add the coating right before baking.

Congratulations on finding another recipe, closer to what you wanted. Do note that the commenter also wants to remove the soda, and is speaking in future tense. S/he hasn't actually tried it with said changes and the other commenters didn't have the trouble. I would not follow that first comment. Check the recipe's troubleshooting tips, instead. Chilling the shaped cookies well before baking, as it says (that timid ”few minutes” should be longer than a literal ”few”), especially if the kitchen is warm, will set the butter and keep it from melting before the dough structure firms up sufficiently. That first commenter said s/he was “aware” of how chilled the dough should be, but not that s/he’d actually done it. And that's assuming it wasn't a troll post. But ironic? Yes! There seems to be a fad of using confectioner's sugar in cookies. There are a bunch of shortbread recipes out there which claim it's requred. Considering that masses of shortbread were made long before specialty sugars were easily available to home cooks, this is puzzling to me. If you cream your butter and sugar properly, which is a chore by hand, but only requires a good bowl that fits in the crook of your elbow and a strong wooden spoon, you don't need pre-pulverized sugar. Certainly not with a mixer. Please let us know the results if you try again!