Refreshing and Easy to Eat Chilled Ochazuke

Thanks to Taiga's planning, Shirou, Saber and Rin take a trip to the waterpark, Waku Waku Zaboom, where they run into Lancer and Archer who challenge them to a beach volleyball game. With Rin and Saber both exhausted after a day of fun, what will Shirou serve for today's meal?