Okay, I got it. Page 123 of the Montcrieff-Kilmartin (1981) translation. Your version:
On leaving the church I knelt down before the alter, and as I stood up I
smelled all of a sudden a bittersweet almond odour(*) escaping from the
hawthorns, and noticed on the flowers little places whiter than the rest,
on which I supposed this scent must be hidden like the taste of marzipan
under a dusting of breadcrumbs(**) or like the cheeks of Mlle Vinteuil
under their red freckles. Despite the silent immobility of the
hawthorns, that intermittent scent was like the murmur of an intense
life which made the altar vibrate as a rural hedge probed by living
antennae where, on some stamens(***) which were almost red and which
seemed to have kept a springlike virulence, one thought to see the
provoking power of insects now metamorphosed into flowers.(****)
(*) I get away with it this time.
(**) I haven't done very well with `comme sous les parties gratinées le
goût d'une frangipane', but being culinary it was never really supposed
to be translated.
(***) `étamines' can mean both `stamens' and `bunting'. I have translated
it once each way; neither really seems right.
(****) Phew.
For **, they have "as the taste of an almond cake lay beneath the burned parts."
For ***, here's the whole sentence: "Despite the motionless silence of the hawthorns, these gusts of fragrance came to me like the murmuring of an intense organic life, with which the whole altar was quivering like a hedgerow explored by living antennae, of which I was reminded by seeing some stamens, almost red in colour, which seemed to have kept the springtime virulence, the irritant power of stinging insects now transmuted into flowers."
Whew, indeed! But you seem to have been right about the stamens. All this buzzing sensuality is more or less in contrast to the Vinteuil girl, wouldn't you say, who unlike MP himself has not apparently begun to feel the hormonal stirrings of adolescence. Then, a few pages later, there is Francoise's grisly murder of the chicken! And after that Legrandin's carnal buttocks! And then, in an ecstasy of hawthorn (and other flowers, but mainly hawthorn)--Gilberte! My, my--bring on the smelling salts!
-alga