Details: This is just a random shopping site I found that sells something that seems like the same product: https://shopee.sg/%E3%80%90Made-in-Japan%E3%80%91-Tohato-Vanilla-Thick-Vanilla-Milk-Japan-Food-Sweets-Biscuits-Snacks%E3%80%90Direct-from-Japan%E3%80%91-i.219170680.7136070901
This is just two butter cookies with vanilla filling sandwiched in between. The vanilla filling has a very powerful vanilla flavor and is very sweet. I’d argue that the vanilla filling is more potent than that of cheaper brands, like Nabisco vanilla cookies. A good quality cookie, but a bit intense.