Thanks to PETO for this morning’s challenge.
I enjoyed this. Not too easy, but nothing held me up for too long. In fact what took the longest in parsing was me overthinking, when the solution was invariably simpler than I expected. Some great clues. Thank you Peto.

ACROSS
1. Recite poem skipping over assertion of truth (7)
DECLAIM
[o]DE (poem, skipping O (over)) + CLAIM (assertion of truth)
5. Sour-tempered fictional detective arresting rotund character (6)
MOROSE
MORSE (fictional detective) arresting O (rotund character)
8. Moralist disturbed by knight’s offence involving loss of grace (6,3)
MORTAL SIN
(MORALIST)* (*disturbed) by N (knight)
9. A carriage sent back out of consideration (5)
APART
A + TRAP< (carriage, <sent back)
11. Endlessly encountered in religious woman’s guiding spirit (5)
NUMEN
ME[t] (encountered, endlessly) in NUN (religious woman)
12. Agreement concerned with protecting old musical instrument (9)
ACCORDION
ACCORD (agreement) + IN (concerned with) protecting O (old)
13. Tell of Dicky employing engineers without having to pay (4-4)
TOLL-FREE
(TELL OF)* (*dicky) employing RE (engineers)
15. Peacekeepers on drugs reportedly for anxiety (6)
UNEASE
UN (peacekeepers) on “E’s” (drugs, “reportedly”)
17. Unmitigated sanction wife ignored (6)
ARRANT
[w]ARRANT (sanction, W (wife) ignored)
19. Systematic investigation concerning small church organ earlier (8)
RESEARCH
RE (concerning) + (S (small) + CH (church)); EAR (organ) earlier
22. Hypocritical after interrupting during Religious Education (9)
INSINCERE
SINCE (after) interrupting IN (during) + RE (Religious Education)
23. Dance company not available outside Gambia’s capital (5)
CONGA
CO (company) + (NA (not available) outside G[ambia’s] (capital))
24. Essential to expel emissions from resin used in varnish (5)
ELEMI
[exp]EL EMI[ssions] (essential to)
25. Replacement component’s new strap packed by American salesman (5,4)
SPARE PART
(STRAP)* (new) packed by A (American) + REP (salesman)
26. Robust scrutiny without resistance (6)
STURDY
STUDY (scrutiny) without R (resistance)
27. Extremely surprised by jar he’d initially disregarded (7)
SHOCKED
SHOCK (jar) + [h]E’D (initially disregarded)
DOWN
1. Serving as proof in case involving deranged monster (13)
DEMONSTRATIVE
DATIVE (case) involving (MONSTER)* (*deranged)
2. Chewy sweet stuff infused with absinthe originally by the Spanish (7)
CARAMEL
CRAM (stuff) infused with A[bsinthe] (originally) by EL (the, Spanish)
3. Leading amateur gets to win for a second time (5)
AGAIN
A[mateur] (leading) gets GAIN (to win)
4. Ill-judged post dividing opinion briefly (8)
MISTAKEN
STAKE (post) dividing MIN[d] (opinion, briefly)
5. Troublemaker regularly seen in club (6)
MENACE
[s]E[e]N (regularly) in MACE (club)
6. Adjust back row (9)
REARRANGE
REAR (back) + RANGE (row)
7. Leading performer almost capturing old Ugandan leader’s enduring energy (7)
STAMINA
STA[r] (leading performer, almost) capturing AMIN (old Ugandan leader)
10. Easily moved boat on date he organised around the end of September (13)
TENDERHEARTED
TENDER (boat) on (DATE HE)* (*organised) around [Septembe]R (end of)
14. More decorative hedges at home of big- time money manager (9)
FINANCIER
FANCIER (more decorative) hedges IN (at home)
16. List of dishes (including drink) served up by son of Spartan king (8)
MENELAUS
MENU (list of dishes) including ALE< (drink, <served up) by S (son)
18. Characteristic of sixth sense described by soldiers at court (7)
RESPECT
ESP (sixth sense) described by RE (soldiers) at CT (court)
20. Fled with large bag of plunder (7)
RANSACK
FLED (ran) with SACK (large bag)
21. Language unknown beyond Japan’s principal island (6)
JERSEY
ERSE (language) + Y (unknown) beyond J[apan’s] (principal)
23. Belief in somewhat mediocre dogma (5)
CREDO
[medio]CRE DO[gma] (somewhat)
Liked DECLAIM, INSINCERE, DEMONSTRATIVE and TENDERHEARTED.
Thanks, Peto and Oriel!
Having read this week’s Guardian blog which linked to a farewell to the FT’s Crossword Editor, Colin Inman, I ended up at the FT with links to their crossword app, and solving the crossword yesterday and today.
I didn’t enjoy a classical education, so had to check MENELAUS, but otherwise, all pretty straightforward.
Thank you for the blog, Oriel, and Peto for the crossword.
I’d have thought “concerned with” in 12a would have been “on”, and was wondering how “old” could be “i”. Can’t get my head around Royal Engineers — are they engineers, as in 13a, or soldiers, as in 18d? MENELAUS, ELEMI & NUMEN were unknown.
DEMONSTRATIVE and MENELAUS were my picks today. A steady solve with some thought required in the SW corner to finish but satisfying to complete.
Thanks to Oriel for providing explanations for a few I’d only half-parsed like 12a for the same reason as Geoff.
And thanks, Peto.
WordPlodder @6 yesterday didn’t have to wait long to use RE again in 22a today. I thought yesterday’s and today’s offerings were easier than any of last week’s; I suppose its that one’s mind is on the same wavelength as some setters and not as others.
Thanks Peto and Oriel. I really liked the use of “Essential to” (24ac) and “Extremely” (27ac) in their natural meanings.
john@5: Judging by the first two days, we are heading for a RE-markable week.
GDU@3: From Wikipedia, “The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the Sappers, is a corps of the British Army. It provides military engineering and other technical support to the British Armed Forces and is headed by the Chief Royal Engineer.” This means that they can legitimately be described as either soldiers or engineers.
I was enjoying this a lot. Inventive cluing, lovely surfaces, chewy enough parsing, nice references to Morse, Menelaus, Amin until my LOI:
“27. Extremely surprised by jar he’d initially disregarded (7)”
If the parsing is correct, the setter seems to be cluing the same word twice: shock = sutprise = jar.
The “he’d initially disregarded” device yields ED, but you could add that on to most regular verbs with a couple of synonyms.
SPOOKED would fit here.
I think we need jar as a noun here so that the surface suggests – to me at least – a man in a pub enjoying a pint of a beer he doesn’t usually drink.
Or am I missing something?
FrankieG@7 re 27ac: When solving, I certainly took the overall definition as the verb form relating to shocking the mind, and then jar as a noun meaning a physical shock, but I am coming round to your view that the words are not sufficiently distinct in meaning. I would never try to make any link between the way the words in the clue appear in the surface meaning, and the way they are used in the cryptic meaning: indeed I would regard a large number of words used differently in the surface and cryptic meanings as a sign of a good clue.
Thank you for the clarification, Pelham Barton @ 6.
Thanks Peto for a well constructed crossword. I particularly liked JERSEY for the way it misled me and MORTAL SIN for its surface. I used a word finder to get ELEMI and then became irritated with myself for having completely missed what “essential” meant in the clue. Thanks Oriel for the blog and explaining SHOCKED.