Just add mayonnaise

Out walking with George, my dog, I noticed the sign outside the garage advertising a meal deal: sandwiches, crisps and a drink.
'Oh,' I said to George, 'I could just eat a sandwich. A nice egg and mayonnaise one with a packet of cheese crisps.'
We walked on a bit.
'Or a prawn and mayonnaise baguette,' I continued.
We crossed the road to the beach.
'Or tuna mayonnaise.'

George said, 'In fact anything with mayonnaise.'
'Um,' I tried to think of anything that wouldn't have tasted good at that point. 'Yes.'