  During its commissioning phase in 2020, the Spectrometer/Telescope for
Imaging X-rays (STIX) on board the Solar Orbiter spacecraft observed 69
microflares. The two most significant events from this set (of GOES class B2
and B6) were observed on-disk from the spacecraft as well as from Earth and
analysed in terms of the spatial, temporal, and spectral characteristics.
  We complement the observations from the STIX instrument with EUV imagery from
SDO/AIA and GOES soft X-ray data by adding imaging and plasma diagnostics over
different temperature ranges for a detailed microflare case study that is
focussed on energy release and transport.
  Spectral fitting of the STIX data shows clear nonthermal emission for both
microflares studied here. The deduced plasma parameters from DEM reconstruction
as well as spectral fitting roughly agree with the values in the literature for
microflares as do the nonthermal fit parameters from STIX. The observed Neupert
effects and impulsive and gradual phases indicate that both events covered in
this study are consistent with the standard chromospheric evaporation flare
scenario. For the B6 event on 7 June 2020, this interpretation is further
supported by the temporal evolution seen in the DEM profiles of the flare
ribbons and loops. For this event, we also find that accelerated electrons can
roughly account for the required thermal energy. The 6 June 2020 event
demonstrates that STIX can detect nonthermal emission for GOES class B2 events
that is nonetheless smaller than the background rate level. We demonstrate for
the first time how detailed multi-instrument studies of solar flares can be
performed with STIX.
