Simple solution: double-clutch when the car is super cold.
It's made a bit more difficult by the thicker fluid in the clutch circuit when super cold (the pedal doesn't want to return as quickly). After driving a little while, you will feel when the gearbox begins to loosen up, and then you can go back to single-clutching, starting with higher gears, then finally for lower gears.
Accelerating goes like this: Accelerating in 1, lift off/clutch/shift to N, release clutch as the revs fall, clutch/shift to 2 (should easily engage), release clutch and accelerate in 2, repeat 2-3, 3-4. 4-5 and 5-6 are usually close enough not to require more than just a slow shift, plus if it's icy out...
Decelerating (from 4, for illustration): slowing in 4, clutch/shift to N, blip the accelerator while briefly releasing the clutch, clutch/shift to 3 and release clutch quickly before revs fall. All while braking as required (double-clutch heel-toe). Repeat 3-2, and 2-1, with a bigger accelerator blip each time (gears are spaced farther the lower you go). Note: you may have an easier time using this technique to go 2-1 while still rolling instead of hitting 1 from a stop when extremely cold. I know I do!
Note: "release the clutch" above means to do so in a deliberate snap. Slow and easy is not your friend with this technique.
If you're doing this correctly, the second half of the shift should happen with very little resistance. For added smoothness, you can also *slightly* bring up the RPM after your shift is complete if it has fallen below the ideal RPM for the next gear (applies to upshifts more than downshifts, since one has to wait for the RPM to fall enough while in N for the next higher gear to match, so by the time the gear is actually engaged the RPM's have then fallen too low, resulting in a lurch upon clutch release; during downshifting one is usually also slowing down, so the 300-500 rpm loss after the blip while you engage the next gear is more-or-less accounted for by the slower car speed.
In my old Mk4, I changed to GM Synchromesh fluid which aided greatly with cold-weather shifting (all shifting, really, that stuff was amazing), but I have not researched if it also compatible with the Mk7 gearbox...