The present work aims at presenting the first results of the manufacturing and electrochemical testing of a two-cells short stack specifically designed with 3 independent chambers in which central membrane (CM) supported monolithic cells are integrated. The supported-CMs were fabricated by using BCY15 and a polymer PMMA as a pore former agent. The CMs were sintered at 1400°C for 5 hours under static air leading to a porosity content of around 50 ± 3 vol. %. The electrolytes were then deposited onto the CMs by tape casting from an ethanol-based suspension containing BCY15 and 1 wt. % of ZnO, and were sintered at 1350°C for 3 hours. Anode ink containing 60 vol. % BCY15, 40 vol. % NiO and 10 wt. % of graphite was deposited on one electrolyte and sintered at 1350°C for 3 hours. Cathode ink containing 50 vol. % BCY15, 50 vol. % LSCF48 and 10 wt. % of graphite was deposited on the other electrolyte and sintered at 1100°C for 3 hours to avoid delamination and creeping. This processing sequence leads to flat cells having a total thickness lower than 1 mm. 2 cells were integrated in a specifically designed short stack made of INOX 440C, and sealed with Thermoculite 866 LS. The electrochemical performances of the short-stack have been measured in real operating conditions via a dedicated 3-chamber set-up named Real Life Tester (RLT), and compared to those of single cells operated under the same conditions. Results are discussed in terms of cells geometry and microstructure, and stack design improvements are proposed.