diff --git a/package.json b/package.json
index 5aa1e3ed..1ce49b9f 100644
--- a/package.json
+++ b/package.json
@@ -74,12 +74,10 @@
     "@rollup/plugin-json": "6.1.0",
     "@swc/core": "1.7.26",
     "@types/debug": "4.1.12",
-    "@types/fs-extra": "11.0.4",
     "@types/node": "22.5.5",
     "@types/resolve": "1.20.6",
     "bumpp": "^9.5.2",
     "flat": "6.0.1",
-    "fs-extra": "11.2.0",
     "postcss": "8.4.47",
     "postcss-simple-vars": "7.0.1",
     "prettier": "3.3.3",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 3ace6c62..66a7fff7 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -69,9 +69,6 @@ importers:
       '@types/debug':
         specifier: 4.1.12
         version: 4.1.12
-      '@types/fs-extra':
-        specifier: 11.0.4
-        version: 11.0.4
       '@types/node':
         specifier: 22.5.5
         version: 22.5.5
@@ -84,9 +81,6 @@ importers:
       flat:
         specifier: 6.0.1
         version: 6.0.1
-      fs-extra:
-        specifier: 11.2.0
-        version: 11.2.0
       postcss:
         specifier: 8.4.47
         version: 8.4.47
@@ -691,12 +685,6 @@ packages:
   '@types/estree@1.0.5':
     resolution: {integrity: sha512-/kYRxGDLWzHOB7q+wtSUQlFrtcdUccpfy+X+9iMBpHK8QLLhx2wIPYuS5DYtR9Wa/YlZAbIovy7qVdB1Aq6Lyw==}
 
-  '@types/fs-extra@11.0.4':
-    resolution: {integrity: sha512-yTbItCNreRooED33qjunPthRcSjERP1r4MqCZc7wv0u2sUkzTFp45tgUfS5+r7FrZPdmCCNflLhVSP/o+SemsQ==}
-
-  '@types/jsonfile@6.1.4':
-    resolution: {integrity: sha512-D5qGUYwjvnNNextdU59/+fI+spnwtTFmyQP0h+PfIOSkNfpU6AOICUOkm4i0OnSk+NyjdPJrxCDro0sJsWlRpQ==}
-
   '@types/ms@0.7.34':
     resolution: {integrity: sha512-nG96G3Wp6acyAgJqGasjODb+acrI7KltPiRxzHPXnP3NgI28bpQDRv53olbqGXbfcgF5aiiHmO3xpwEpS5Ld9g==}
 
@@ -1012,10 +1000,6 @@ packages:
     resolution: {integrity: sha512-Ld2g8rrAyMYFXBhEqMz8ZAHBi4J4uS1i/CxGMDnjyFWddMXLVcDp051DZfu+t7+ab7Wv6SMqpWmyFIj5UbfFvg==}
     engines: {node: '>=14'}
 
-  fs-extra@11.2.0:
-    resolution: {integrity: sha512-PmDi3uwK5nFuXh7XDTlVnS17xJS7vW36is2+w3xcv8SVxiB4NyATf4ctkVY5bkSjX0Y4nbvZCq1/EjtEyr9ktw==}
-    engines: {node: '>=14.14'}
-
   fs-extra@7.0.1:
     resolution: {integrity: sha512-YJDaCJZEnBmcbw13fvdAM9AwNOJwOzrE4pqMqBq5nFiEqXUqHwlK4B+3pUw6JNvfSPtX05xFHtYy/1ni01eGCw==}
     engines: {node: '>=6 <7 || >=8'}
@@ -1164,9 +1148,6 @@ packages:
   jsonfile@4.0.0:
     resolution: {integrity: sha512-m6F1R3z8jjlf2imQHS2Qez5sjKWQzbuuhuJ/FKYFRZvPE3PuHcSMVZzfsLhGVOkfd20obL5SWEBew5ShlquNxg==}
 
-  jsonfile@6.1.0:
-    resolution: {integrity: sha512-5dgndWOriYSm5cnYaJNhalLNDKOqFwyDB/rr1E9ZsGciGvKPs8R2xYGCacuf3z6K1YKDz182fd+fY3cn3pMqXQ==}
-
   kleur@3.0.3:
     resolution: {integrity: sha512-eTIzlVOSUR+JxdDFepEYcBMtZ9Qqdef+rnzWdRZuMbOywu5tO2w2N7rqjoANZ5k9vywhL6Br1VRjUIgTQx4E8w==}
     engines: {node: '>=6'}
@@ -1723,10 +1704,6 @@ packages:
     resolution: {integrity: sha512-rBJeI5CXAlmy1pV+617WB9J63U6XcazHHF2f2dbJix4XzpUF0RS3Zbj0FGIOCAva5P/d/GBOYaACQ1w+0azUkg==}
     engines: {node: '>= 4.0.0'}
 
-  universalify@2.0.1:
-    resolution: {integrity: sha512-gptHNQghINnc/vTGIk0SOFGFNXw7JVrlRUtConJRlvaw6DuX0wO5Jeko9sWrMBhh+PsYAZ7oXAiOnf/UKogyiw==}
-    engines: {node: '>= 10.0.0'}
-
   uri-js@4.4.1:
     resolution: {integrity: sha512-7rKUyy33Q1yc98pQ1DAmLtwX109F7TIfWlW1Ydo8Wl1ii1SeHieeh0HHfPeL2fMXK6z0s8ecKs9frCuLJvndBg==}
 
@@ -2233,15 +2210,6 @@ snapshots:
 
   '@types/estree@1.0.5': {}
 
-  '@types/fs-extra@11.0.4':
-    dependencies:
-      '@types/jsonfile': 6.1.4
-      '@types/node': 22.5.5
-
-  '@types/jsonfile@6.1.4':
-    dependencies:
-      '@types/node': 22.5.5
-
   '@types/ms@0.7.34': {}
 
   '@types/node@22.5.5':
@@ -2609,12 +2577,6 @@ snapshots:
       cross-spawn: 7.0.3
       signal-exit: 4.1.0
 
-  fs-extra@11.2.0:
-    dependencies:
-      graceful-fs: 4.2.11
-      jsonfile: 6.1.0
-      universalify: 2.0.1
-
   fs-extra@7.0.1:
     dependencies:
       graceful-fs: 4.2.11
@@ -2748,12 +2710,6 @@ snapshots:
     optionalDependencies:
       graceful-fs: 4.2.11
 
-  jsonfile@6.1.0:
-    dependencies:
-      universalify: 2.0.1
-    optionalDependencies:
-      graceful-fs: 4.2.11
-
   kleur@3.0.3: {}
 
   lilconfig@3.1.2: {}
@@ -3235,8 +3191,6 @@ snapshots:
 
   universalify@0.1.2: {}
 
-  universalify@2.0.1: {}
-
   uri-js@4.4.1:
     dependencies:
       punycode: 2.3.1
diff --git a/test/utils.ts b/test/utils.ts
index dd353718..ca9e702c 100644
--- a/test/utils.ts
+++ b/test/utils.ts
@@ -1,8 +1,9 @@
+import fs from 'node:fs'
+import fsp from 'node:fs/promises'
 import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { expect } from 'vitest'
 import execa from 'execa'
-import fs from 'fs-extra'
 import { glob } from 'tinyglobby'
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
@@ -35,8 +36,12 @@ export async function run(
 
   // Write entry files on disk
   await Promise.all(
-    Object.keys(files).map((name) => {
-      return fs.outputFile(path.resolve(testDir, name), files[name], 'utf8')
+    Object.keys(files).map(async (name) => {
+      const filePath = path.resolve(testDir, name)
+      const parentDir = path.dirname(filePath)
+      // Thanks to `recursive: true`, this doesn't fail even if the directory already exists.
+      await fsp.mkdir(parentDir, { recursive: true })
+      return fsp.writeFile(filePath, files[name], 'utf8')
     }),
   )
 
@@ -69,7 +74,7 @@ export async function run(
     logs,
     outDir: path.resolve(testDir, 'dist'),
     getFileContent(filename: string) {
-      return fs.readFile(path.resolve(testDir, filename), 'utf8')
+      return fsp.readFile(path.resolve(testDir, filename), 'utf8')
     },
   }
 }