diff --git a/src/variations/frankenphp/Dockerfile b/src/variations/frankenphp/Dockerfile
index 364fa30a..29a63c59 100644
--- a/src/variations/frankenphp/Dockerfile
+++ b/src/variations/frankenphp/Dockerfile
@@ -146,7 +146,7 @@ LABEL org.opencontainers.image.title="serversideup/php (frankenphp)" \
     COMPOSER_HOME=/composer \
     COMPOSER_MAX_PARALLEL_HTTP=24 \
     DISABLE_DEFAULT_CONFIG=false \
-    FRANKEN_PHP_CONFIG="" \
+    FRANKENPHP_CONFIG="" \
     LOG_OUTPUT_LEVEL=info \
     HEALTHCHECK_PATH="/healthcheck" \
     PHP_DATE_TIMEZONE="UTC" \