Possible Clues:

• Mush
• Molasses plant a class included
• Syrup well described by the Dormouse
• Blandishments from elder maybe to get a class enthralled
• Cloying speech
• Excessive sentiment
• Leading Tesco cereal product is sticky-sweet
• Electra (anag)
• A chapel that's empty in service say showing sentimentality
• Sticky stuff, sort of lac found in e.g. pine