diff --git a/packages/kit/src/runtime/server/cookie.js b/packages/kit/src/runtime/server/cookie.js
index f8d872207005..54119b411f0e 100644
--- a/packages/kit/src/runtime/server/cookie.js
+++ b/packages/kit/src/runtime/server/cookie.js
@@ -107,13 +107,23 @@ export function get_cookies(request, url, trailing_slash) {
 		 * @param {import('cookie').CookieSerializeOptions} opts
 		 */
 		set(name, value, opts = {}) {
+			return this.set_internal(name, value, { with_defaults: true, ...opts });
+		},
+
+		/**
+		 * @param {string} name
+		 * @param {string} value
+		 * @param {import('cookie').CookieSerializeOptions & { with_defaults?: boolean }} opts
+		 */
+		set_internal(name, value, opts = {}) {
 			let path = opts.path ?? default_path;
+			const with_defaults = opts.with_defaults ?? true;
 
 			new_cookies[name] = {
 				name,
 				value,
 				options: {
-					...defaults,
+					...(with_defaults ? defaults : {}),
 					...opts,
 					path
 				}
diff --git a/packages/kit/src/runtime/server/fetch.js b/packages/kit/src/runtime/server/fetch.js
index ca5df895f9a8..90abe108a6f9 100644
--- a/packages/kit/src/runtime/server/fetch.js
+++ b/packages/kit/src/runtime/server/fetch.js
@@ -131,11 +131,10 @@ export function create_fetch({ event, options, manifest, state, get_cookie_heade
 						const { name, value, ...options } = set_cookie_parser.parseString(str);
 
 						// options.sameSite is string, something more specific is required - type cast is safe
-						event.cookies.set(
-							name,
-							value,
-							/** @type {import('cookie').CookieSerializeOptions} */ (options)
-						);
+						event.cookies.set_internal(name, value, {
+							with_defaults: false,
+							.../** @type {import('cookie').CookieSerializeOptions} */ (options)
+						});
 					}
 				}