Peel and chop the onions and place them in a large frying pan (skillet) along with the duck fat. Cook gently over a low heat for about 10 minutes to soften. Meanwhile, wash the okra, trim off the two ends then cut the stems into ½" (1cm) lengths. Add these to the onions in the pan.
Peel the tomatoes (see our Hot Tips if you're not sure how) then de-seed them and roughly chop into bite-size pieces. Add these to the pan.