Can you use frozen peaches? If so, how?

Thaw, drain and use as you would fresh peaches. I've done this many times. We have a beautiful 'you pick' peach orchard and it's hard to stop picking as the peaches are gorgeous. Needless to say, I freeze most of them. One pound of frozen peaches equals 3 cups fresh.

Sort of an oddball recipe, but it depends partly on the peaches to hydrate the cake mix; frozen (and defrosted) would probably work better than fresh for that.

Like the other (Flame Peach Cobbler) recipe, the original recipe at the Emily Henry website (linked in the Food52 recipe) suggests using two 1 lb. cans of peaches in lieu of fresh ones, so I'm guessing that frozen peaches would work. I suppose you will want to defrost them first, then proceed with the rest of the recipe.

Best of luck.