I bought cakes of "Chez Chima (シェ・シーマ)", a cake shop of Ichigawa (市ヶ谷) at Isetan Sinjyuku (伊勢丹新宿).They have several branches in Tokyo and one of which is located in Isetan, a posh department store. Chez Chima is famous for "creme d'angel" and cream puff (for your information, their cream puff is often sold out before early-evening).
Mont blanc cassis
The creme d'angel was definitely good. Combination of whipped cream cheese and rich raspberry sauce was unmistakable. Other cakes were also not so showiness, but the taste was sophisticated. One piece of cake costs around JPY450, relatively reasonable compared to other cake shops in Isetan. My rating is 3.7 out of 5. Gochiso-samadeshita!