Flour Bakery + Cafe opened it's Back Bay location just after noon on Thursday and business has been booming. 

"Completely killed on our first full lunch at F4 today. If u came/waited thank u for your patience+hope lunch was great. Tmrw will be better!" owner Joanne Chang-Myers tweeted Monday. 

The cafe, Flour's fourth, is at 131 Clarendon St., in the former Hard Rock Cafe. Flour also has locations in Central Square, the South End and Fort Point. 

The Back Bay spot seats up to 50 people, according to Eater. It will be open Monday to Friday from 7 a.m. to 8 p.m., Saturday from 8 a.m. to 6 p.m. and Sunday from 9 a.m. to 3 p.m.