Heat a medium saucepan on a gentle heat, add cabbage and herbs. Place on the lid and allow the cabbage to steam in its own juices.
Put lentils in a medium saucepan, cover by an inch of water, and add the onion, garlic, tomato paste, passata, stock powder and optional tabasco; bring to a boil, reduce heat and simmer until cooked to a thickish soup.
Finely slice the potatoes (use a mandolin or processor, or with a knife, about ½ cm thick) and steam for 10 minutes or until just tender.
Make the white sauce by putting all ingredients into a blender, blending til smooth, pouring into a small saucepan and stirring constantly until thickened.
Grease a deep baking dish or casserole dish which has a close-fitting lid e.g. Pyrex or Le Creuset)
Layer in the dish as follows:1/3 of the potatoes1/3 of the cabbage1/2 of the lentil mixture1/3 of the white sauce1/2 of remaining potatoes1/2 of remaining cabbageRest of lentils1/2 of remaining white sauceRemaining potatoesRemaining cabbageRemaining white sauceBreadcrumbs Bake for 40 minutes, in a moderate oven, placing on the lid for the last 15 minutes to prevent top burning. Test it is cooked through by piercing with a knife. It should be very soft, top crisp and sauce bubbling. Allow to stand for 10 minutes before serving.