Yeah, his phone.

'Wait a minute! I could just look up how to make ice cream on my phone! It can still access the internet!' Touya realized. "Hold on, give me a second," he told them. "Actually, Linze, could you give me a hand?"

"Uh, sure, I don't mind lending one," she replied, and they headed up to his room where he gave her some paper, and a quill. Then he pulled out his smart phone.

"Ice cream recipes, search," he muttered.

"What's that thing?" Linze asked.

"Oh, it's a handy magical device," he told her, partially being honest, as it HAd been modified to run on magic. "I can use it to read up on all sorts of knowledge, though there are some limits," he added, which was also true, it didn't have this world's writing in it.

"Oh... I can't read it though... Is it in Ishen text?" she asked.

"Something like that," he chuckled. Actually, come to think of it, the Sex Note was in Japanese (obviously translated to English for this story). Did it automatically translate to the language of whoever read and wrote in it via whatever magic it ran off of? He'd have to ask Mika, as she's already seen it. "Just write down the instructions I give you," he told her, and she nodded as he first rattled off the ingredients, then how to prepare them.

...

Some time later, they had a batch ready. Linze had used magic to freeze the ice cream, and he had done the whisking. Which tired him out, but they had several servings, and upon trying it, Aeru immediately expressed bliss. "It's delicious!" she exclaimed.

"So cool and tasty..." Linze moaned in euphoria as she took her own bite.

"I'll definitely add this to the menu!" Aeru informed Touya. "Thank you so much!" She headed out with the instructions.

...

"What, you had some while I was away!?" Elize demanded, having returned. While Touya hand Linze had been getting the instructions, and the group had prepared the ice cream, Elize had gone back to the guild to check the quests to see if there were any they should take tomorrow, and she had thus missed out. "I wanted to try some..."

"Well, we still have some ingredients, so we can make more!" Mika promised. "Touya, can you stir again?"

Despite the throbbing in his arms, Touya resignedly agreed.