I used two colors that I had ( Bambu black matte and marble ), but any black and white should be perfect.

I have printed it with no prime tower, very fast and less material loss. The result for me it's very good like this. 
Even if for me it's fine like this, you can try and add “Ironing” for top layer if you want a smoother surface finish.
 

You can import the model as single object with multiple parts and change the color for each part.

The snowflake part it's only 0.4mm height and it's inside the coaster. 
The actual print from the picture is done with 0.2mm layer height,  2 walls, 15% infill and no priming tower. ( used Bambu AMS, total printing time 35min )