Is this what put REESE WITHERSPOON in a grouchy mood before her headline-making run-in with that cop?

New Mommy – proud she’d dropped baby weight by strict dieting – damn near had a cow when she discovered french toast she’d gobbled for breakfast on the Atlanta set of her new movie, “The Good Lie,” was smothered in REAL syrup and REAL butter!… SHRIEEEK!…“Reese had sent specific instructions to the on-set chef that she wanted sugar-free syrup – and margarine instead of butter,” said My SpyWitness.

“After gobbling the toast, she said, ‘Wow, that tasted like the REAL thing!’ – then checked the container and discovered it really WAS!

"‘Oh, my God,’ she screamed, ‘I just ate over a thousand calories!’ ”

Turns out the chef never got her instructions!

Reese, furious at first, finally shrugged and said: “I’ll just do an extra hour on the StairMaster!”

(Now that’s our good-natured gal!)