There are two places to eat at Burg Eltz – a lower restaurant (below the castle) and a café on the terrace just outside the entrance to the inner courtyard. On nice days, the views are spectacular! Local wines from the Eltz vineyards are also available at these venues.
We had cheesecake and a drink at the terrace café on our first visit. The cake was delicious and the beverage refreshing. The prices were reasonable, especially nice since the remote location could give some reason to hike up the prices for their captive audience.
While both times we visited the restaurants were not too crowded, I can imagine in the height of the summer season on a beautiful day that seating would be difficult during lunch hours.
There are two self service restaurant right on the grounds of the castle. The Oberschaenke that seats 120 poeple and is located around the castle well and inside the old Goldsmith's Lodge. The Unterschaenke seats 100 people around the lime tree and a further 90 people in the romantic portico. The restaurants serve some fast food and drinks - not a culinary delight - just a quick meal whilst exploring the region!