diff --git a/middleman-core/lib/middleman-core/application.rb b/middleman-core/lib/middleman-core/application.rb
index 0de3e485..b275d69c 100644
--- a/middleman-core/lib/middleman-core/application.rb
+++ b/middleman-core/lib/middleman-core/application.rb
@@ -261,6 +261,12 @@ module Middleman
       # Eval config.
       evaluate_configuration!
 
+      # Run any `configure` blocks for the current environment.
+      execute_callbacks([:configure, config[:environment]])
+
+      # Run any `configure` blocks for the current mode.
+      execute_callbacks([:configure, config[:mode]])
+
       # Post parsing, pre-extension callback
       execute_callbacks(:after_configuration_eval)
 
@@ -292,12 +298,6 @@ module Middleman
         logger.debug "== Reading: #{config[:environment]} config"
         config_context.instance_eval File.read(env_config), env_config, 1
       end
-
-      # Run any `configure` blocks for the current environment.
-      execute_callbacks([:configure, config[:environment]])
-
-      # Run any `configure` blocks for the current mode.
-      execute_callbacks([:configure, config[:mode]])
     end
 
     # Clean up missing Tilt exts
diff --git a/middleman-core/lib/middleman-core/callback_manager.rb b/middleman-core/lib/middleman-core/callback_manager.rb
index 5f9ca360..73b635e3 100644
--- a/middleman-core/lib/middleman-core/callback_manager.rb
+++ b/middleman-core/lib/middleman-core/callback_manager.rb
@@ -9,6 +9,7 @@ module Middleman
     Contract Any
     def initialize
       @callbacks = ::Hamster.hash
+      @subscribers = ::Hamster.vector
     end
 
     Contract RespondTo[:define_singleton_method], ArrayOf[Symbol] => Any
@@ -28,6 +29,7 @@ module Middleman
       end
 
       install_target.define_singleton_method(:callbacks_for, &method(:callbacks_for))
+      install_target.define_singleton_method(:subscribe_to_callbacks, &method(:subscribe))
     end
 
     Contract Or[Symbol, ArrayOf[Symbol]], Proc => Any
@@ -39,9 +41,15 @@ module Middleman
       end
     end
 
+    Contract Proc => Any
+    def subscribe(&block)
+      @subscribers = @subscribers.push(block)
+    end
+
     Contract Or[Symbol, ArrayOf[Symbol]], Maybe[ArrayOf[Any]], Maybe[RespondTo[:instance_exec]] => Any
     def execute(keys, args=[], scope=self)
       callbacks_for(keys).each { |b| scope.instance_exec(*args, &b) }
+      @subscribers.each { |b| scope.instance_exec(keys, *args, &b) }
     end
 
     Contract Or[Symbol, ArrayOf[Symbol]] => ::Hamster::Vector
diff --git a/middleman-core/lib/middleman-core/config_context.rb b/middleman-core/lib/middleman-core/config_context.rb
index ded3ae15..1f9f32f6 100644
--- a/middleman-core/lib/middleman-core/config_context.rb
+++ b/middleman-core/lib/middleman-core/config_context.rb
@@ -15,19 +15,11 @@ module Middleman
       @app = app
       @template_context_class = template_context_class
 
-      sub_callbacks = [:before_build, :after_build, :configure, :after_configuration, :ready]
-
       @callbacks = ::Middleman::CallbackManager.new
-      @callbacks.install_methods!(self, sub_callbacks)
+      @callbacks.install_methods!(self, [:before_build, :after_build, :configure, :after_configuration, :ready])
 
       # Trigger internal callbacks when app level are executed.
-      self_context = self
-
-      sub_callbacks.each do |key|
-        app.send(key) do |*args|
-          self_context.execute_callbacks(key, args)
-        end
-      end
+      app.subscribe_to_callbacks(&method(:execute_callbacks))
     end
 
     def helpers(*helper_modules, &block)