diff --git a/lib/sinatra/assetpack/class_methods.rb b/lib/sinatra/assetpack/class_methods.rb
index beb1e38..4e9f754 100644
--- a/lib/sinatra/assetpack/class_methods.rb
+++ b/lib/sinatra/assetpack/class_methods.rb
@@ -87,7 +87,8 @@ def add_individual_routes!
 
               @template_cache.fetch(fn) {
                 settings.assets.fetch_dynamic_asset(fn) {
-                  out = render format.to_sym, File.read(fn), :filename => fn
+                  settings.templates[fn.to_sym] = [Proc.new { File.read(fn) }, fn]
+                  out = render format.to_sym, fn.to_sym, :filename => fn
                   out = asset_filter_css(out)  if fmt == 'css'
                   out
                 }