A lot of glass jars used to have that kind of pattern on the bottom; I don’t even think I have one in the house anymore, but you can get cookie stamps that make the same pattern. Or you might find one of the old jars at a thrift store.
Thanks. I’ll check around here first, have tons of older stuff. And have a couple cookie stamps. But I’ll be honest, they look really good but there are others with a higher priority if I get the ambition to bake cookies.