A strange turn of phrase...

Dear native English speakers,

Several times, I have come across a turn of phrase which puzzles me. Could you please tell me in which context you would use "too long a car", "too spicy a soup" or any phrase of the likes?

Another similar term which enjoys the power of making me feel perplexed is "an idiot of a boy" or someting alike.

What is the difference, if any, between these phrases and "a car too long", "a soup too spicy", "an idiot boy", etc?

Many thanks in advance.

These phrases exaggerate the adjectives being used to either emphasize the extent of the adjective in question, or to give you a "read-between-the-lines" impression of how the speaker feels about these qualities. I believe these phrases are what you would call a "hyperbole."

For instance, simply saying "a long car" or "the spicy soup" doesn't really tell you much (and are pretty generic descriptions), but saying "too long a car" and "too spicy a soup" gives you the impression that these are qualities that the speaker doesn't find appealing.

Though "that boy's an idiot" adequately describes how stupid the boy is, "that is one idiot of a boy" conveys the extent of the boy's idiocy.

Hope I've made sense.

Examples of how you would use these phrases:

"Yes, I said I was looking for a car big enough to transport my family, but that last one you showed me was too long a car for me to drive in the city."

"The chicken gumbo I ordered was too spicy a soup for me to enjoy."

"Wow! I've taught many a difficult child, but that one sure is one idiot of a boy!"

Many thanks, Elaine!
It was too weird a turn of phrase for me to fully understand its meaning on my own.

By the way, can they be pluralised?

"Idiot of boys" sounds a bit odd, but that is just my opinion and I can not even think of a plural equivalent for "too long a car"...