4085 If I've Told You Once ... by Ploy

Ploy gave us a fun puzzle with a neatly integrated theme. The theme was a quote from Gertrude Stein, “A rose is a rose is a rose”. The letter pairs to be omitted from clues could form the Latin phrase MUTATO NOMINE. This could be translated as “by a change of name”. This explained how to resolve clashes in the grid. Four names, Dolina, Tamara, Peter and Cherry had to be changed to other words. The other clashes had to be changed in the opposite way, revealing the name ROSE in four places and revealing the name GERTRUDE STEIN. The name of the work where the quote appears could be discerned in the central column, “Sacred Emily”, though this was not to be highlighted.

Removed letter-pairs are shown in []
Across
1 Alternative present - common ingredient of sweet and sour sauce (8)
PERTNESS Anagram PRESENT + S (letter shared by SWEET and SOUR)
6 Distant call - muso who's first to go? (4)
SOHO [MU]SO + (w)HO
11 Inability to decide about getting time off - back trouble (7)
ABOULIA ABOU(t) + AIL reversed
13 Extract of giant amaranth in spice mixture (6)
TAMARA Hidden
14 In a mirage, a lion deserted swallow hole (6)
DOLINA Anagram (in a [MI]rage) A LION + D (deserted)
16 Cod for one. About right for skipper (7)
CAPERER CAPE + RE + R (Ref. Cape Cod)
18 Watch American amateur - a long shot (6)
ANALOG A (amateur) + Anagram A LONG
21 Mayflies with no wings move very slowly (4)
EDGE (S)EDGE(S)
23 Dish of potatoes and eggs, with Asti (unopened) (6)
ROESTI ROE + (a)STI
24 Tale of adventure is fun for the listener (5)
GESTE Homophone JEST
26 Redesigned tinder boxes without a gummy mixture (7)
DEXTRIN X (without) in Anagram TINDER
29 Species of atom is not one lacking neutron (7)
ISOTONE IS (n)OT ONE less n (neutron)
30 Denoting country where no one is moderate (6)
GENTLE GENTILE less I
31 Soups effervescing seconds after recipe is ignored (5)
BISKS B(r)ISK + S (seconds)
32 A way to escape from a river (5)
MEUSE 2 definitions
35 Till Australian has summer in Paris, residing in Puerto Rico (5)
PETER ÉTÉ in PR
37 Discarded deer's sweetbread cooked in chip pan in Pa's absence (7)
INCHPIN Anagram IN CHIP PAN less PA
38 Like Dawn, Laura's crazy about gold (7)
AURORAL OR (gold) in Anagram LAURA
39 That woman's parting prayer: "Comfort for Ed" (6)
CHERRY HER in CRY
40 Has a nomad party in governor's office (7)
SATRAPY ‘S + A + Anagram ([NO]mad) PARTY
41 Bear in Banff is taking in river (4)
DREE R ([TA]KING) in DEE

 
Down
1 Heavy knife mostly protecting Dane in foreign field (6)
PADANG DA[NE] in PANG(a)
2 Wood found in the bonfire (4)
EBON Hidden
3 Bird spotted in Etruria every now and then (3)
TUI even letters eTrUrIa
4 Karate costume turns up on German island (4)
EIGG GIE reversed + G (German)
5 Silence arrives in a rush (5)
STARR ST + ARR
7 Eccentricity evident in weird motel dish (6)
OMELET E in Anagram MOTEL
8 Two points in Jewish law about Passover food (7)
HAROSET SE in TORAH reversed
9 Shell initially succeeds over old, localised plants at sea (4)
ORES ORE + S(hell)
10 Virgin, possibly in Ireland, guarded by elder (7)
AIRLINE IRL in AINÉ
12 One councillor starts to enjoy dealing with land (5)
ACRED A CR (councillor) + E(njoy) D(ealing)
15 Thick-lipped solera barrels under the table (7)
LABROSE Anagram SOLERA + B (barrels)
17 Our speech is out of place in a place of prayer (9)
PROSEUCHE Anagram OUR SPEECH
19 Half-educated Latvian (4)
LETT LETT(ered)
20 Are German cars turning up delivering things left behind? (7)
RESIDUA ‘RE (are) + AUDIS reversed
22 Plant climbing well in terribly drear setting (7)
DROSERA SO reversed in Anagram DREAR
25 Perhaps take shell off prawn prepared with hint of umami (6)
UNWRAP U(mami) + Anagram PRAWN
27 Need group of Indian states with energy (not atomic) (6)
EGENCY AGENCY changing A (atomic) to E (energy)
28 From outset, I'll insist on returning clay mineral (6)
ILLITE Hidden reversed
31 Bulge in bowl -- it's in the same place, upside down (4)
BIAS SA (it = sex appeal) + IB all reversed
32 Angular measurement regularly met in semicircles (3)
MIL third letters seMicIrcLes
33 Is he, by today, in cast? (4)
SHED ‘S + HE + D ([TO]day)
34 Soon empty the old Ottawa River channel (4)
SNYE S(oo)N + YE
36 Hill fort not having the first bats (3)
TOR Anagram (f)ORT