  Dual quasars, two active supermassive black holes at galactic scales,
represent crucial objects for studying the impact of galaxy mergers and quasar
activity on the star formation rate (SFR) within their host galaxies,
particularly at cosmic noon when SFR peaks. We present JWST/MIRI mid-infrared
integral field spectroscopy of J074922.96+225511.7, a dual quasar with a
projected separation of 3.8 kilo-parsec at a redshift $z$ of 2.17. We detect
spatially extended [Fe II] 5.34$\rm \mu$m and polycyclic aromatic hydrocarbon
(PAH) 3.3$\mu$m emissions from the star formation activity in its host galaxy.
We derive the SFR of 10$^{3.0\pm0.2}$ M$_{\odot}$ yr$^{-1}$ using PAH
3.3$\mu$m, which is five times higher than that derived from the cutoff
luminosity of the infrared luminosity function for galaxies at $z\sim2$. While
the SFR of J0749+2255 agrees with that of star-forming galaxies of comparable
stellar mass at the same redshifts, its molecular gas content falls short of
expectations based on the molecular Kennicutt-Schmidt law. This discrepancy may
result from molecular gas depletion due to the longer elevated stage of star
formation, even after the molecular gas reservoir is depleted. We do not
observe any quasar-driven outflow that impacts PAH and [Fe II] in the host
galaxy based on the spatially resolved maps. From the expected flux in
PAH-based star formation, the [Fe II] line likely originates from the
star-forming regions in the host galaxy. Our study highlights the stardust
nature of J0749+2255, indicating a potential connection between the dual quasar
phase and intense star formation activities.
