If CANDLE is coded as BDEOFM, how is BASKET coded in the same way?

Explanation

1. 01

   Shift BDEOFM back by 1 to get ACDNEL.

2. 02

   ACDNEL is CANDLE with each pair swapped: CA to AC, ND to DN, LE to EL.

3. 03

   So the code swaps each pair and moves every letter 1 place forward.

4. 04

   BASKET: pairs BA, SK, ET swap to AB, KS, TE, giving ABKSTE; +1 gives BCLTUF.