diff --git a/local/recipes/kde/plasma-desktop/recipe.toml b/local/recipes/kde/plasma-desktop/recipe.toml
index 68033b06f7..2bbce843dd 100644
--- a/local/recipes/kde/plasma-desktop/recipe.toml
+++ b/local/recipes/kde/plasma-desktop/recipe.toml
@@ -96,9 +96,14 @@ done
 # does not happen here. Adding the includes is what upstream should have done --
 # CMake documents both as requiring an explicit include().
 # Idempotent: guarded on the text not already being present.
+# Two separate sed calls rather than one with an embedded \n: that form has to
+# survive TOML unescaping, then the shell, then sed's own insert parsing, and it
+# did not -- the emitted file began with "nclude(CheckIncludeFiles)", losing the
+# leading 'i', and configure died with
+#   ConfigureChecks.cmake:2 (nclude): Unknown CMake command
 if ! grep -q '^include(CheckFunctionExists)' "${COOKBOOK_SOURCE}/ConfigureChecks.cmake"; then
-    sed -i '1i include(CheckFunctionExists)\ninclude(CheckIncludeFiles)' \
-        "${COOKBOOK_SOURCE}/ConfigureChecks.cmake"
+    sed -i '1i include(CheckIncludeFiles)' "${COOKBOOK_SOURCE}/ConfigureChecks.cmake"
+    sed -i '1i include(CheckFunctionExists)' "${COOKBOOK_SOURCE}/ConfigureChecks.cmake"
 fi
 
 # ConfigureChecks.cmake:7 double-prefixes the XKB path when cross-compiling.