diff --git a/package-lock.json b/package-lock.json
index 590ae522..a1384182 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6,8 +6,11 @@
   "packages": {
     "": {
       "name": "@netlify/functions",
-      "version": "0.0.1",
+      "version": "0.1.0",
       "license": "MIT",
+      "dependencies": {
+        "is-promise": "^2.2.2"
+      },
       "devDependencies": {
         "@commitlint/cli": "^11.0.0",
         "@commitlint/config-conventional": "^11.0.0",
@@ -5154,8 +5157,7 @@
     "node_modules/is-promise": {
       "version": "2.2.2",
       "resolved": "https://registry.npmjs.org/is-promise/-/is-promise-2.2.2.tgz",
-      "integrity": "sha512-+lP4/6lKUBfQjZ2pdxThZvLUAafmZb8OAxFb8XXtiQmS35INgr85hdOGoEs124ez1FCnZJt6jau/T+alh58QFQ==",
-      "dev": true
+      "integrity": "sha512-+lP4/6lKUBfQjZ2pdxThZvLUAafmZb8OAxFb8XXtiQmS35INgr85hdOGoEs124ez1FCnZJt6jau/T+alh58QFQ=="
     },
     "node_modules/is-regex": {
       "version": "1.1.2",
@@ -13228,8 +13230,7 @@
     "is-promise": {
       "version": "2.2.2",
       "resolved": "https://registry.npmjs.org/is-promise/-/is-promise-2.2.2.tgz",
-      "integrity": "sha512-+lP4/6lKUBfQjZ2pdxThZvLUAafmZb8OAxFb8XXtiQmS35INgr85hdOGoEs124ez1FCnZJt6jau/T+alh58QFQ==",
-      "dev": true
+      "integrity": "sha512-+lP4/6lKUBfQjZ2pdxThZvLUAafmZb8OAxFb8XXtiQmS35INgr85hdOGoEs124ez1FCnZJt6jau/T+alh58QFQ=="
     },
     "is-regex": {
       "version": "1.1.2",
diff --git a/package.json b/package.json
index 597fc931..6e79abef 100644
--- a/package.json
+++ b/package.json
@@ -49,7 +49,9 @@
   "directories": {
     "test": "test"
   },
-  "dependencies": {},
+  "dependencies": {
+    "is-promise": "^2.2.2"
+  },
   "devDependencies": {
     "@commitlint/cli": "^11.0.0",
     "@commitlint/config-conventional": "^11.0.0",
diff --git a/src/lib/builder_functions.js b/src/lib/builder_functions.js
index b9e4e47a..ec843350 100644
--- a/src/lib/builder_functions.js
+++ b/src/lib/builder_functions.js
@@ -1,3 +1,5 @@
+const isPromise = require('is-promise')
+
 const { HTTP_STATUS_METHOD_NOT_ALLOWED, HTTP_STATUS_OK } = require('./consts')
 
 const augmentResponse = (response) => {
@@ -12,19 +14,24 @@ const augmentResponse = (response) => {
 }
 
 // eslint-disable-next-line promise/prefer-await-to-callbacks
-const wrapHandler = (handler) => async (event, context, callback) => {
+const wrapHandler = (handler) => (event, context, callback) => {
   if (event.httpMethod !== 'GET' && event.httpMethod !== 'HEAD') {
-    return {
+    return Promise.resolve({
       body: 'Method Not Allowed',
       statusCode: HTTP_STATUS_METHOD_NOT_ALLOWED,
-    }
+    })
   }
 
   // eslint-disable-next-line promise/prefer-await-to-callbacks
   const wrappedCallback = (error, response) => callback(error, augmentResponse(response))
-  const response = await handler(event, context, wrappedCallback)
+  const execution = handler(event, context, wrappedCallback)
+
+  if (isPromise(execution)) {
+    // eslint-disable-next-line promise/prefer-await-to-then
+    return execution.then(augmentResponse)
+  }
 
-  return augmentResponse(response)
+  return execution
 }
 
 module.exports = { builderFunction: wrapHandler }
diff --git a/test/builder_functions.js b/test/builder_functions.js
index 61932aa5..5880c34e 100644
--- a/test/builder_functions.js
+++ b/test/builder_functions.js
@@ -132,3 +132,21 @@ test('Returns a 405 error for requests using the PATCH method', async (t) => {
 
   t.deepEqual(response, { body: 'Method Not Allowed', statusCode: 405 })
 })
+
+test('Preserves errors thrown inside the wrapped handler', async (t) => {
+  const error = new Error('Uh-oh!')
+
+  error.someProperty = ':thumbsdown:'
+
+  const myHandler = async () => {
+    const asyncTask = new Promise((resolve) => {
+      setTimeout(resolve, 0)
+    })
+
+    await asyncTask
+
+    throw error
+  }
+
+  await t.throwsAsync(invokeLambda(builderFunction(myHandler)), { is: error })
+})