event.twig

Date is {{post.ee.event_start_date}}

single.php

<?php

	include_once('timber-event-espresso.php');
	
	$context = Timber::get_context();
	if (is_event_espresso_single()) { //psudo code
		$context['post'] = new TimberEventEspresso();
	}
	Timber::render('event.twig', $context);

timber-event-espresso.php

<?php

class TimberEventEspresso extends TimberPost {


	public function ee() {
		$id = $this->ID;
		$ee = new EE_Event($id); //whatever you do to delcare a new EE_Event based on ID. This is psudo code
		$this->ee = $ee;
	}

}