The former That '70s Show costars toured Bruges, Belgium on Sunday morning in a horse-drawn carriage to take in the cobblestone streets and ancient bridges.
"They seemed very much in love," Christine Rohart, sales manager of the Hotel Montanus, tells PEOPLE. "They were holding hands, they were giving kisses to each other."
A day prior, Kutcher, 35, and Kunis, 29, explored the city on foot, stopping into the local market and famous chocolate shops just before enjoying a meal at the triple-Michelin starred Carmelite restaurant.
"Mila ate a local dish called Hoppescheuten, which she had never heard of but wanted to try," a source tells PEOPLE. "She just thought 'why not?' and thought it was wonderful."
The source adds: "Ashton ate a special seven course menu that cost 210 euros. It is a very famous menu, where the main dish is rabbit with prunes. It is classic food but with a modern dish."
The couple enjoyed their meals so much, they "came into the chef's kitchen afterwards to thank him," the source says.
Prior to their weekend in Bruges, Kutcher and Kunis double dated with another high profile couple on Friday night – Channing Tatum and his expectant wife, Jenna Dewan-Tatum. The group was spotted at the Barbican Theatre in London, where they took in a performance of the opera Sunken Garden.