diff --git a/client/utils/build-challenges.js b/client/utils/build-challenges.js
index 04e0d8c86a8..207330f7782 100644
--- a/client/utils/build-challenges.js
+++ b/client/utils/build-challenges.js
@@ -2,43 +2,69 @@ const path = require('path');
 
 const _ = require('lodash');
 
-const envData = require('../config/env.json');
 const { getChallengesForLang } = require('../../curriculum/get-challenges');
 
 const {
   getContentDir,
-  getBlockCreator
+  getBlockCreator,
+  getSuperblocks,
+  superBlockToFilename
 } = require('../../curriculum/build-curriculum');
-const { getBlockStructure } = require('../../curriculum/file-handler');
-const { getSuperblocks } = require('../../curriculum/build-curriculum');
+const {
+  getBlockStructure,
+  getSuperblockStructure
+} = require('../../curriculum/file-handler');
+const { transformSuperBlock } = require('../../curriculum/build-superblock');
+const { getSuperOrder } = require('../../curriculum/utils');
 
-const { curriculumLocale } = envData;
+const curriculumLocale = process.env.CURRICULUM_LOCALE || 'english';
 
 exports.localeChallengesRootDir = getContentDir(curriculumLocale);
 
 const blockCreator = getBlockCreator(curriculumLocale);
 
+function getBlockMetadata(block, superBlock) {
+  // Compute metadata for the given block in the specified superblock
+  const sbFilename = superBlockToFilename[superBlock];
+  const sbData = getSuperblockStructure(sbFilename);
+  const blocks = transformSuperBlock(sbData, {
+    showComingSoon: process.env.SHOW_UPCOMING_CHANGES === 'true'
+  });
+
+  const order = blocks.findIndex(b => b.dashedName === block);
+  const superOrder = getSuperOrder(superBlock);
+
+  if (order === -1) {
+    throw new Error(`Block ${block} not found in superblock ${superBlock}`);
+  }
+
+  return { order, superOrder };
+}
+
 exports.replaceChallengeNodes = () => {
   return async function replaceChallengeNodes(filePath) {
     const parentDir = path.dirname(filePath);
     const block = path.basename(parentDir);
     const filename = path.basename(filePath);
 
-    console.log(`Replacing challenge node for ${filePath}`);
+    console.log(`Replacing challenge nodes for ${filePath}`);
     const meta = getBlockStructure(block);
     const superblocks = getSuperblocks(block);
 
-    const challenge = await blockCreator.createChallenge({
-      filename,
-      block,
-      meta,
-      isAudited: true
-    });
+    // Create a challenge for each superblock containing this block
+    const challenges = await Promise.all(
+      superblocks.map(async superBlock => {
+        const { order, superOrder } = getBlockMetadata(block, superBlock);
+        return blockCreator.createChallenge({
+          filename,
+          block,
+          meta: { ...meta, superBlock, order, superOrder },
+          isAudited: true
+        });
+      })
+    );
 
-    return superblocks.map(superBlock => ({
-      ...challenge,
-      superBlock
-    }));
+    return challenges;
   };
 };
 
diff --git a/tools/client-plugins/gatsby-source-challenges/gatsby-node.js b/tools/client-plugins/gatsby-source-challenges/gatsby-node.js
index 54e2c5248c1..a646bfe2f23 100644
--- a/tools/client-plugins/gatsby-source-challenges/gatsby-node.js
+++ b/tools/client-plugins/gatsby-source-challenges/gatsby-node.js
@@ -1,6 +1,4 @@
-const path = require('path');
 const chokidar = require('chokidar');
-const readdirp = require('readdirp');
 
 const { createChallengeNode } = require('./create-challenge-nodes');
 
@@ -36,68 +34,34 @@ exports.sourceNodes = function sourceChallengesSourceNodes(
     cwd: curriculumPath
   });
 
+  function handleChallengeUpdate(filePath, action = 'changed') {
+    return onSourceChange(filePath)
+      .then(challenges => {
+        const actionText = action === 'added' ? 'creating' : 'replacing';
+        reporter.info(
+          `Challenge file ${action}: ${filePath}, ${actionText} challengeNodes with ids ${challenges.map(({ id }) => id).join(', ')}`
+        );
+        challenges.forEach(challenge =>
+          createVisibleChallenge(challenge, { isReloading: true })
+        );
+      })
+      .catch(e =>
+        reporter.error(
+          `fcc-replace-challenge\nattempting to replace ${filePath}\n\n${e.message}\n${e.stack ? `  ${e.stack}` : ''}`
+        )
+      );
+  }
+
+  // On file change, replace only the changed challenge. The key is ensuring
+  // onSourceChange returns a challenge with complete metadata.
   watcher.on('change', filePath =>
-    /\.md?$/.test(filePath)
-      ? onSourceChange(filePath)
-          .then(challenges => {
-            reporter.info(
-              `
-File changed at ${filePath}, replacing challengeNodes with ids ${challenges.map(({ id }) => id).join(', ')}
-              `
-            );
-            challenges.forEach(challenge =>
-              createVisibleChallenge(challenge, { isReloading: true })
-            );
-          })
-          .catch(e =>
-            reporter.error(`fcc-replace-challenge
-  attempting to replace ${filePath}
-
-  ${e.message}
-  ${e.stack}
-
-  `)
-          )
-      : null
+    /\.md?$/.test(filePath) ? handleChallengeUpdate(filePath, 'changed') : null
   );
 
-  // if a file is added, that might change the order of the challenges in the
-  // containing block, so we recreate them all
+  // On file add, replace just the new challenge.
   watcher.on('add', filePath => {
-    if (/\.md?$/.test(filePath)) {
-      const blockPath = path.dirname(filePath);
-      const fullBlockPath = path.join(
-        __dirname,
-        '../../../curriculum/challenges/english/',
-        blockPath
-      );
-      readdirp(fullBlockPath, { fileFilter: '*.md' })
-        .on('data', entry => {
-          const { path: siblingPath } = entry;
-          const relativePath = path.join(blockPath, siblingPath);
-          onSourceChange(relativePath)
-            .then(challenges => {
-              reporter.info(
-                `
-File changed at ${relativePath}, replacing challengeNodes with ids ${challenges.map(({ id }) => id).join(', ')}
-            `
-              );
-              challenges.forEach(challenge =>
-                createVisibleChallenge(challenge)
-              );
-            })
-            .catch(e =>
-              reporter.error(`fcc-replace-challenge
-attempting to replace ${relativePath}
-
-${e.message}
-
-`)
-            );
-        })
-        .on('warn', error => console.error('non-fatal error', error))
-        .on('error', error => console.error('fatal error', error));
-    }
+    if (!/\.md?$/.test(filePath)) return;
+    handleChallengeUpdate(filePath, 'added');
   });
 
   function sourceAndCreateNodes() {