Can I wire my under cabinet lighting in parallel?
Three LEDs per resistor is a common arrangement for fixtures designed to be connected directly to 12V.

No external resistor is required.

Your plan to connect them all in parallel is correct. Just make sure that the total current (0.3A per fixture &times; 6 fixtures = 1.8A) doesn't exceed the capacity of the power supply.

The lamps can be "daisy chained" with one cable running from the power supply to the first lamp, then a cable from there to the next lamp, and so on. However, electrically, this is still a parallel connection across the power supply, not a series connection. Each lamp is still getting the full 12V.