diff --git a/fava.nix b/fava.nix
index 489afd6..21b05ce 100644
--- a/fava.nix
+++ b/fava.nix
@@ -8,10 +8,10 @@ let
   # Build a Python environment with fava and all extensions.
   # This avoids duplicate package conflicts by letting Python resolve
   # shared dependencies (like fava itself) in a single environment.
-  python = cfg.package.pythonModule;
+  favaPython = pkgs.python3Packages.fava;
   favaWithExtensions = if cfg.extensions == [] then cfg.package else
     let
-      env = python.withPackages (ps: [ cfg.package ] ++ cfg.extensions);
+      env = favaPython.pythonModule.withPackages (ps: [ favaPython ] ++ cfg.extensions);
     in env;
 
 in {