Possible Clues:

• Undercooked morsel that's eaten
• The artist took another bite from the toasted dish
• Rate rib roast a snack?
• Gunners on Rome's river returning for a snack
• Seldom encountered by British, Italian cheese dish
• See 8 Across
• Arbiter cooked snack
• Piece of cheese on toast — lightly cooked piece
• Food that might entice an American coin collector?
• Artist getting about nibbled a toastie