Those type of Yaoi are really hard to find, I only read one where the seme was the butler but I forgot what it was called. Try looking on Google because it helped me find lists on here but I don't know if someone made a Butler seme x uke Master list tho.
Try these
http://www.mangago.zone/read-manga/yurusareta_uta/
http://www.mangago.zone/read-manga/fukigen_kareshi_no_saraikata/
http://www.mangago.zone/read-manga/shitsuji_kyoushi_no_renai_jugyou/
http://www.mangago.zone/read-manga/shitsuji_game/
http://www.mangago.zone/read-manga/hachimitsu_ouji_wa_shitsuji_ni_madou/
http://www.mangago.zone/read-manga/yogoto_nayamashii_niwa_de/
http://www.mangago.zone/read-manga/shitsuji_hiiragi/
http://www.mangago.zone/read-manga/shitsuji_wa_oose_no_mama_ni/
http://www.mangago.zone/read-manga/onozomi_no_mama_ni/ (chapter 1 and 6)
I've read Blue Morning and I don't kinda enjoy the idea of the master being the top and the butler being the bottom, is there any yaoi manga where the servant/butler is top while their master is the bottom? Thanks ヾ(☆▽☆)