Borlotti & Red Wine Pie topped with kale mash

Heat the oil in a large, deep frying pan or saucepan. Add the onion, celery, carrot and garlic and cook over a medium heat for 8-10 minutes until softened. Add the chestnut mushrooms and cook for a further 3-4 minutes.
Turn down the heat, add the tomato purée and plain flour to the pan and stir until there are no lumps of flour. Add the puy lentils and borlotti beans, followed by the red wine, stock and thyme. Bring to the boil, stirring continually, then reduce to a gentle simmer and cook for 45 minutes (uncovered), stirring occasionally.
Whilst the filling is cooking, peel the potatoes and cut into large-ish chunks. Boil for 15-20 minutes until completely cooked through, then drain and mash with the margarine and milk.
Remove all the stalks from the curly kale, and roughly chop the leaves. Heat 1 tablespoon oil in a small frying pan and sauté the kale for 5 minutes. Tip into the mash and mix well to combine.
Place your filling in a pie dish and carefully spoon the kale mash onto the top. Place on a baking tray and bake in the oven for 20-25 minutes until the top is crisp and golden and the filling is bubbling around the edges.