Help with parsing two clues please:
9A Cheeky boy keeps burning cheesecake (3-2). Answer appears to be Pin-up (cheesecake). I assume cheeky boy is pup, but if so how can 'in' be burning?!
14D System ECHR delivered cryptically in thirty-one days (9). Answer seems to be Machinery, ie May round anagram of ECHR, but this leaves 'in'. Cannot see where this comes from, because the 'in' in the clue has already been used to put the anagram inside May. Can anyone explain please?