Alright, I found the answer. For the benefit of others…you need to activate the custom content type Portfolio Projects in Jetpack.
The Portfolio custom post type gives you an easy way to manage and showcase projects on your site. If your theme doesn’t support it yet, you can enable the Portfolio custom post type by activating the Custom Content Types module in your Jetpack settings. Then, go to Settings → Writing in your WordPress Dashboard and check the Portfolio Projects option under “Your Custom Content Types.”
You can then choose to display the portfolio using the portfolio shortcode ( [portfolio] ) or with a link to the portfolio in the menu.