diff --git a/packages/core/src/cell.ts b/packages/core/src/cell.ts
index 05528312..3e6aab2e 100644
--- a/packages/core/src/cell.ts
+++ b/packages/core/src/cell.ts
@@ -16,19 +16,19 @@ class ThebeCodeCell extends PassiveCellRenderer implements IThebeCell {
   session?: ThebeSession;
   executionCount: number | null;
   notebook?: ThebeNotebook;
-  protected initialOutputs: IOutput[];
   protected busy: boolean;
   protected events: EventEmitter;
 
   constructor(
     id: string,
     source: string,
+    outputs: IOutput[],
     config: Config,
     metadata: JsonObject,
     rendermime: IRenderMimeRegistry,
     notebook?: ThebeNotebook,
   ) {
-    super(id, rendermime);
+    super(id, outputs, rendermime);
     this.kind = 'code';
     this.events = new EventEmitter(id, config, EventSubject.cell, this);
     this.notebook = notebook;
@@ -36,7 +36,6 @@ class ThebeCodeCell extends PassiveCellRenderer implements IThebeCell {
     this.metadata = metadata;
     this.busy = false;
     this.executionCount = null;
-    this.initialOutputs = [];
     console.debug('thebe:cell constructor', this);
   }
 
@@ -49,6 +48,7 @@ class ThebeCodeCell extends PassiveCellRenderer implements IThebeCell {
     const cell = new ThebeCodeCell(
       icc.id ?? shortId(),
       ensureString(icc.source),
+      icc.outputs ?? [],
       config,
       icc.metadata,
       rendermime,
diff --git a/packages/core/src/markdown.ts b/packages/core/src/markdown.ts
index 8dd8d8c6..227e691a 100644
--- a/packages/core/src/markdown.ts
+++ b/packages/core/src/markdown.ts
@@ -29,7 +29,7 @@ export default class ThebeMarkdownCell extends PassiveCellRenderer implements IT
     rendermime: IRenderMimeRegistry,
     notebook?: ThebeNotebook,
   ) {
-    super(id, rendermime);
+    super(id, [], rendermime);
     this.kind = 'markdown';
     this.id = id;
     this.notebook = notebook;
diff --git a/packages/core/src/notebook.ts b/packages/core/src/notebook.ts
index 90d1af61..9c1dba93 100644
--- a/packages/core/src/notebook.ts
+++ b/packages/core/src/notebook.ts
@@ -53,6 +53,7 @@ class ThebeNotebook {
       const cell = new ThebeCodeCell(
         c.id,
         c.source,
+        c.outputs ?? [],
         config,
         metadata,
         notebook.rendermime,
diff --git a/packages/core/src/passive.ts b/packages/core/src/passive.ts
index 1bf71a7c..efc57953 100644
--- a/packages/core/src/passive.ts
+++ b/packages/core/src/passive.ts
@@ -7,20 +7,35 @@ import { makeMathjaxOptions } from './options';
 import { Widget } from '@lumino/widgets';
 import { MessageLoop } from '@lumino/messaging';
 
+function assert(condition: any, msg?: string): asserts condition {
+  if (!condition) {
+    throw new Error(msg);
+  }
+}
+
 class PassiveCellRenderer implements IPassiveCell {
   readonly id: string;
   readonly rendermime: IRenderMimeRegistry;
+  initialOutputs: nbformat.IOutput[];
+
   protected model: OutputAreaModel;
   protected area: OutputArea;
 
-  constructor(id: string, rendermime?: IRenderMimeRegistry, mathjax?: MathjaxOptions) {
+  constructor(
+    id: string,
+    initialOutputs?: nbformat.IOutput[],
+    rendermime?: IRenderMimeRegistry,
+    mathjax?: MathjaxOptions,
+  ) {
     this.id = id;
     this.rendermime = rendermime ?? makeRenderMimeRegistry(mathjax ?? makeMathjaxOptions());
+    assert(this.rendermime, 'no rendermime');
     this.model = new OutputAreaModel({ trusted: true });
     this.area = new OutputArea({
       model: this.model,
       rendermime: this.rendermime,
     });
+    this.initialOutputs = initialOutputs ?? [];
   }
 
   /**
@@ -34,7 +49,10 @@ class PassiveCellRenderer implements IPassiveCell {
     return this.area.isAttached;
   }
 
-  attachToDOM(el?: HTMLElement, strict = false) {
+  attachToDOM(
+    el?: HTMLElement,
+    opts: { strict?: boolean; appendExisting?: boolean } = { strict: false, appendExisting: true },
+  ) {
     if (!this.area || !el) {
       console.error(
         `thebe:renderer:attachToDOM - could not attach to DOM - area: ${this.area}, el: ${el}`,
@@ -44,11 +62,11 @@ class PassiveCellRenderer implements IPassiveCell {
     if (this.area.isAttached) {
       // TODO should we detach and reattach?
       console.debug(`thebe:renderer:attachToDOM - already attached`);
-      if (strict) return;
+      if (opts.strict) return;
     } else {
       // if the target element has contents, preserve it but wrap it in our output area
       console.debug(`thebe:renderer:attachToDOM ${this.id} - appending existing contents`);
-      if (el.innerHTML) {
+      if (opts.appendExisting && el.innerHTML) {
         this.area.model.add({
           output_type: 'display_data',
           data: {
diff --git a/packages/core/src/types.ts b/packages/core/src/types.ts
index a3c1e58a..88010854 100644
--- a/packages/core/src/types.ts
+++ b/packages/core/src/types.ts
@@ -6,9 +6,7 @@ import type ThebeServer from './server';
 import type { ServerStatusEvent } from './events';
 import type { Config } from './config';
 import type ThebeNotebook from './notebook';
-
 export type CellKind = 'code' | 'markdown';
-
 export type JsonObject = Record<string, any>;
 export type SessionIModel = Session.IModel;
 export type KernelISpecModels = KernelSpecAPI.ISpecModels;
@@ -86,8 +84,9 @@ export interface IPassiveCell {
   readonly rendermime: IRenderMimeRegistry;
   readonly isAttachedToDOM: boolean;
   readonly outputs: IOutput[];
+  readonly initialOutputs: IOutput[];
 
-  attachToDOM(el?: HTMLElement): void;
+  attachToDOM(el?: HTMLElement, opts?: { strict?: boolean; appendExisting?: boolean }): void;
   setOutputText(text: string): void;
   clear(): void;
   clearOnError(error?: any): void;
diff --git a/packages/react/src/hooks/notebook.ts b/packages/react/src/hooks/notebook.ts
index 3c10641c..839d8628 100644
--- a/packages/react/src/hooks/notebook.ts
+++ b/packages/react/src/hooks/notebook.ts
@@ -179,17 +179,19 @@ export function useNotebook(
             .map((_, idx) => (node) => {
               console.debug(`new ref[${idx}] - attaching to dom...`, node);
               if (node != null) {
-                cells[idx].attachToDOM(node);
-                cells[idx].render(cells[idx].outputs);
-                cells[idx].setOutputText('attached to DOM [OUTPUT]');
+                cells[idx].attachToDOM(node, { appendExisting: false });
+                cells[idx].render(cells[idx].initialOutputs);
+                // cells[idx].setOutputText('attached to DOM [OUTPUT]');
 
+                console.log('about to hydrate widgets', cells[idx].outputs);
                 cells[idx].outputs.forEach((output, i) => {
+                  console.log('output', i, output);
                   if (
                     (output.output_type === 'display_data' ||
                       output.output_type === 'execute_result') &&
                     typeof output.data === 'object'
                   ) {
-                    console.log('output', i, output);
+                    console.log('output:confirmed', i, output);
                     const mimeBundles = output.data as IExecuteResult;
                     if (mimeBundles[WIDGET_VIEW_MIMETYPE]) {
                       const model_id = (mimeBundles[WIDGET_VIEW_MIMETYPE] as { model_id: string })