A low-profile flat resonant metasurface grating for achieving strong blazing and auto-collimation at microwaves is experimentally demonstrated. The design utilizes a planar approach for blazed gratings, but is different in its fundamental operation compared to phase-modulated blazed metasurface gratings. It operates similar to 3D perfectly blazed resonant cavity gratings, but realized with a planar strip resonator of lowest order resonance in each unit-cell. The structure is capable of achieving strong blazing (i.e. low specular reflection and high m = −1 diffraction). Simulations and Measurements confirm strong auto-collimation blazing in the Transverse Magnetic polarization at microwave frequencies.