Possible Clues:

• With 58-Down, common cake ingredient
• Vehicle coughing and spluttering over a plain
• Cream-soda flavor
• Pod that produces flavouring
• Quite ordinary article in fancy house
• Nothing special to find love in a toilet, when head over heels
• Sundae staple
• Ordinary against Australia – turned up exhausted
• Dull, metaphorically
• Supposedly plain article found in big house