  We have detected the T~Tauri star, DO Tauri, in a 0.6$''$-resolution VLA map
of 43.3 GHz ($\lambda$ = 7 mm) continuum emission. The 43 GHz flux density lies
on the same power-law slope defined by 89 to 232 GHz measurements, F$_\nu$
$\propto \nu^{\alpha}$ with index $\alpha$ = 2.39$\pm$0.23, confirming that the
43.3 GHz emission is thermal radiation from circumstellar dust. Upper limits to
the flux densities at 8.4 and 22.5 GHz constrain the contribution of free-free
emission from a compact ionized wind to less than 49\%. The dust emissivity
index, $\beta$, is $0.39\pm$0.23, if the emission is optically thin. Fitting a
model of a thin circumstellar disk to the observed spectral energy distribution
gives $\beta = 0.6\pm0.3$, consistent with the power-law derivation. Both
values are substantially lower than is generally accepted for the interstellar
medium, suggesting grain growth. Given the youth of DO Tau and the early
evolutionary state of its circumstellar disk, this result implies that mm-size
grains have already formed by the early T-Tauri phase.
