MacArthur Park .....
The song is named after MacArthur Park, a park in Los Angeles, California. Its lyrics, which include the memorable line "Someone left the cake out in the rain", are more symbolic than descriptive, beginning as a poem about love, then moving into a lover's lament.
Ah... ok, I get it now.
I get it. I always have. The lyrics being symbolic are not all that strange - just weird. You should weep for the recipe he will never have again. A love-cake ruined, never to be baked again.
I'm a poet at heart, so I suppose I can understand things mere mortals are left to ponder.