diff --git a/src/DefaultBuilder/src/WebApplicationBuilder.cs b/src/DefaultBuilder/src/WebApplicationBuilder.cs
index dbe2a9ad7dc8..8a95266c7b35 100644
--- a/src/DefaultBuilder/src/WebApplicationBuilder.cs
+++ b/src/DefaultBuilder/src/WebApplicationBuilder.cs
@@ -137,7 +137,8 @@ internal WebApplicationBuilder(WebApplicationOptions options, bool slim, Action<
             {
                 AspNetCore.WebHost.ConfigureWebDefaultsCore(webHostBuilder);
 
-                webHostBuilder.Configure(ConfigureEmptyApplication);
+                // Runs inline.
+                webHostBuilder.Configure(ConfigureApplication);
 
                 webHostBuilder.UseSetting(WebHostDefaults.ApplicationKey, _hostApplicationBuilder.Environment.ApplicationName ?? "");
                 webHostBuilder.UseSetting(WebHostDefaults.PreventHostingStartupKey, Configuration[WebHostDefaults.PreventHostingStartupKey]);
@@ -260,46 +261,6 @@ public WebApplication Build()
     }
 
     private void ConfigureApplication(WebHostBuilderContext context, IApplicationBuilder app)
-    {
-        ConfigureApplicationCore(
-            context,
-            app,
-            processAuthMiddlewares: () =>
-            {
-                Debug.Assert(_builtApplication is not null);
-
-                // Process authorization and authentication middlewares independently to avoid
-                // registering middlewares for services that do not exist
-                var serviceProviderIsService = _builtApplication.Services.GetService<IServiceProviderIsService>();
-                if (serviceProviderIsService?.IsService(typeof(IAuthenticationSchemeProvider)) is true)
-                {
-                    // Don't add more than one instance of the middleware
-                    if (!_builtApplication.Properties.ContainsKey(AuthenticationMiddlewareSetKey))
-                    {
-                        // The Use invocations will set the property on the outer pipeline,
-                        // but we want to set it on the inner pipeline as well.
-                        _builtApplication.Properties[AuthenticationMiddlewareSetKey] = true;
-                        app.UseAuthentication();
-                    }
-                }
-
-                if (serviceProviderIsService?.IsService(typeof(IAuthorizationHandlerProvider)) is true)
-                {
-                    if (!_builtApplication.Properties.ContainsKey(AuthorizationMiddlewareSetKey))
-                    {
-                        _builtApplication.Properties[AuthorizationMiddlewareSetKey] = true;
-                        app.UseAuthorization();
-                    }
-                }
-            });
-    }
-
-    private void ConfigureEmptyApplication(WebHostBuilderContext context, IApplicationBuilder app)
-    {
-        ConfigureApplicationCore(context, app, processAuthMiddlewares: null);
-    }
-
-    private void ConfigureApplicationCore(WebHostBuilderContext context, IApplicationBuilder app, Action? processAuthMiddlewares)
     {
         Debug.Assert(_builtApplication is not null);
 
@@ -340,7 +301,29 @@ private void ConfigureApplicationCore(WebHostBuilderContext context, IApplicatio
             }
         }
 
-        processAuthMiddlewares?.Invoke();
+        // Process authorization and authentication middlewares independently to avoid
+        // registering middlewares for services that do not exist
+        var serviceProviderIsService = _builtApplication.Services.GetService<IServiceProviderIsService>();
+        if (serviceProviderIsService?.IsService(typeof(IAuthenticationSchemeProvider)) is true)
+        {
+            // Don't add more than one instance of the middleware
+            if (!_builtApplication.Properties.ContainsKey(AuthenticationMiddlewareSetKey))
+            {
+                // The Use invocations will set the property on the outer pipeline,
+                // but we want to set it on the inner pipeline as well.
+                _builtApplication.Properties[AuthenticationMiddlewareSetKey] = true;
+                app.UseAuthentication();
+            }
+        }
+
+        if (serviceProviderIsService?.IsService(typeof(IAuthorizationHandlerProvider)) is true)
+        {
+            if (!_builtApplication.Properties.ContainsKey(AuthorizationMiddlewareSetKey))
+            {
+                _builtApplication.Properties[AuthorizationMiddlewareSetKey] = true;
+                app.UseAuthorization();
+            }
+        }
 
         // Wire the source pipeline to run in the destination pipeline
         app.Use(next =>
diff --git a/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs b/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
index 73c87deeb48a..eba3433d5d3d 100644
--- a/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
+++ b/src/DefaultBuilder/test/Microsoft.AspNetCore.Tests/WebApplicationTests.cs
@@ -2260,17 +2260,14 @@ public void CanObserveDefaultServicesInServiceCollection(CreateBuilderFunc creat
     }
 
     [Theory]
-    [InlineData(true)]
-    [InlineData(false)]
-    public async Task RegisterAuthMiddlewaresCorrectly(bool useSlimBuilder)
+    [MemberData(nameof(CreateBuilderFuncs))]
+    public async Task RegisterAuthMiddlewaresCorrectly(CreateBuilderFunc createBuilder)
     {
         var helloEndpointCalled = false;
         var customMiddlewareExecuted = false;
         var username = "foobar";
 
-        var builder = useSlimBuilder ?
-            WebApplication.CreateSlimBuilder() :
-            WebApplication.CreateBuilder();
+        var builder = createBuilder();
 
         builder.Services.AddAuthorization();
         builder.Services.AddAuthentication("testSchemeName")
@@ -2278,13 +2275,6 @@ public async Task RegisterAuthMiddlewaresCorrectly(bool useSlimBuilder)
         builder.WebHost.UseTestServer();
         await using var app = builder.Build();
 
-        if (useSlimBuilder)
-        {
-            // NOTE: CreateSlimBuilder doesn't support auto registration of auth middleware, so need to do it explicitly
-            app.UseAuthentication();
-            app.UseAuthorization();
-        }
-
         app.Use(next =>
         {
             return async context =>
@@ -2314,11 +2304,11 @@ public async Task RegisterAuthMiddlewaresCorrectly(bool useSlimBuilder)
         Assert.True(customMiddlewareExecuted);
     }
 
-    [Fact]
-    public async Task SupportsDisablingMiddlewareAutoRegistration()
+    [Theory]
+    [MemberData(nameof(CreateBuilderFuncs))]
+    public async Task SupportsDisablingMiddlewareAutoRegistration(CreateBuilderFunc createBuilder)
     {
-        // NOTE: CreateSlimBuilder doesn't support auto registration of auth middleware
-        var builder = WebApplication.CreateBuilder();
+        var builder = createBuilder();
         builder.Services.AddAuthorization();
         builder.Services.AddAuthentication("testSchemeName")
             .AddScheme<AuthenticationSchemeOptions, UberHandler>("testSchemeName", "testDisplayName", _ => { });