I told my friends this, and described Twix, and they said, "Go to Riverville's. They make all kinds of confections, and he'll probably be able to make some for you." (I am taking the liberty of translating Japanese names here.) Riverville is the name of a local confectioner, and he has his own shop. I'd even herd the name before; another local friend had recommended them, and the name had also come up when teachers were talking about local places to buy goodies.
So today after school I googled the place, and it turns out it's only about a five-minute walk away from my apartment. I've even almost walked past it-- it was just aroound the corner from an intersection I've walked by many times.
I walk in, and the first thing I notice is the smell-- the warm, toasty smell you get when you bake cookies that have a lot of butter. You can't fake it, and the shop is permeated. To my left is a display of beautifully formed traditional Japanese bean confections, dyed an array of colors and in an assortment of shapes; in front is a table piled high with pre-wrapped cookies, slices of cake, and dorayaki (sweetened bean-filled pancakes). In front is a refrigerated display case filled with the most gorgeous cakes-- chocolate mousse, mont blanc, some red globes, many others-- and to the right of that display case was another one filled with chocolates.
A bunch of people were making things in the back, but one of them came out as soon as I stepped in the door. I asked him if he could make Twix for me, and he couldn't. But I am not the kind of person who can easily walk out of a shop like this empty-handed. I asked him about the chocolates, if they select a different kind of chocolate for each kind of truffle. They do. Thye had green tea and white chocolate, Earl Grey and milk chocolate, lavender honey and dark chocolate, praline, framboise, orange, and a few others. He had me at "Earl Grey"-- that might just be my very favorite flavor for a truffle, and I haven't had it since college.
I asked what the buttery smell was, and they were baking green tea financiers. Financiers are a type of cookie that I have never even made. He also explained to me all of the cakes: the red domes were straberry mousse atop a cake made with ground pistachios, and what looked like a plain chocolate mousse was actually Earl Grey-infused chocolate mousse around a core of Earl Grey and vanilla flavored creme brulee. They had buttercream-filled French macaroons in many varieties (lemon, strawberry, chocolate, coffee caramel, and black tea) and they even had a type of pie filled with caramel and nuts that he said might be a bit similar to the Twix.
I only got a few things-- if I bought everything I wanted there I knew I'd spend hundreds of dollars and eat myself sick. The Earl Grey truffle was a tiny little one-bite morsel, but the ratio of chocolate to cream on the inside was a not-quite-gooey perfect, the tea and milk chocolate flavors balanced perfectly, and the shell wispy thin and instantly melt-in-your-mouth. (It is difficult to get a chocolate coating so delicate; I can't do it. Heck, I can't even temper chocolate on my own.) The nut pie was vaguely, vaguely reminiscent of a Twix-- the caramel filling was about the same consistency, maybe a bit stiffer, but you could taste the not-quite-burnt sugar and the butter that went into it, and the crust was the kind of brown and flaky you get when you use a lot of butter, you are careful to leave some of it in large chunks, and you bake the whole thing in a perfectly super-hot oven.
His things are expensive, but they are worth it. I can tell what sort of work went into making them. My only regret is that I didn't discover the place sooner! I've been living here for over a year now, and this was my first visit! I don't think I can ever go to any of the other sweets shops, or ever buy them from the grocery store, ever again.