The finished recipe. Warm Lentils with Smoked Mackerel and BeetrootIngredients 1 to 6. 180 g Cooked lentils (Cooked weight, green or brown. A pouch is already this.). 80 g Smoked mackerel (As sold. Most of the fat in any dish it is in.). 100 g Cooked beetroot (Vacuum-packed, not pickled. Pickled beetroot carries vinegar and usually sulphites.). 30 g Red onion. 1 tsp, about 6 g Dijon mustard. 2 tsp, about 12 g Creamed horseradishIngredients 7 to 9. 5 g Olive oil. A splash Cider vinegar. A handful, chopped Fresh parsleyStep 1. Warm the lentils in a pan with a splash of water for three minutes.Step 2. Stir in the mustard, oil, vinegar, the red onion sliced very thin, and the parsley. Season.Step 3. Flake the mackerel over the lentils, skin removed, and add the beetroot in wedges. Spoon the horseradish on top.