I am generally dubious about the whole A La Recherche de Temps Perdu thing, a) because I suspect (I've never read it) the novel is a load of pretentious tosh and b) because it is scientifically incorrect. When Marcel Proust tediously droned on about childhood memories evoked by the taste of a Madeleine cake dipped in tea, he was using the wrong sense as a trigger. Maybe he should have gone for a smell.
While it apparently isn't true that the sense of smell is the strongest when evoking memories (vision wins), it does seem from the way the neurons fire in the brain that the first time a smell gets tied to a particular object or activity it kicks of considerably more energetic brain activity than it does on other occasions - so first smell associations appear to be powerful.
I had one brought back to me the other day when, for reasons we don't need to go into, I ended up boiling a pan of mushy peas on the stove for 25 minutes. I was instantly transported to my grandma's house. That smell was the smell of being at my grandmother's, yet until that moment I hadn't realized it - or I had forgotten.
For some reason, she always used dried peas, so they would almost always be either soaking or cooking until mushy, with that distinctive smell that if I were a wine expert I would suggest had hints of flannel and bicarbonate of soda. More often than not it would be black peas (nothing to do with black-eyed peas) on the go. This particular pea variant, actually a dark brown, was a favourite in Lancashire mill towns - a speciality for bonfire night alongside parkin and jacket potatoes, but also an everyday treat. On my aunt's council estate in Rochdale there was even a black pea man who came round selling them every evening. He started with a bicycle, but ended up with a converted ice cream van.
If you ever have the joy of eating mushy peas, or even better mushy black peas (they are nicer - nuttier and with more complex flavours), one word of warning. I have had people (mostly ignorant southerners) say to me that mushy peas are tasteless. If this is your opinion, you haven't eaten them properly. They MUST have a pinch of salt and a good sloshing of vinegar - more vinegar than you could possibly imagine was necessary. (First time round keep adding a bit at a time until you see why.) This transforms the flavour and makes them delectable. What's not to love?
P.S. In looking for a picture of black peas to include I came across a picture of mushy peas that was actually pea puree. Mushy peas should not be a puree - they still have their pea form, but have exuded enough gunk to have a thick 'gravy'. If they end up as literal mush you have gone to far.