Heat the butter and olive oil in a saucepan over a medium heat and fry the onion, carrot and bay leaf until they have softened.
Add the lamb mince and fry until browned. Season with salt and pepper and then pour in the stock, worcestershire sauce and tomato puree. Season and bring to the boil, then reduce the heat and leave to simmer for 20-30 minutes, stirring every so often.
The finished mince mixture shouldn’t be wet at all. If it’s still a bit liquidy after 30 minutes, turn up the heat and let it bubble away for a few minutes. Set aside and leave to cool.
Place the potatoes in a large pan of salted water and boil for 15-20 minutes, until tender. Drain and pass through a ricer until smooth. Set aside to cool.
Mix the corn flour through the cooled mashed potato. Roll balls of the potato in the palm of your hand and add 1 tablespoon of the mince filling to the centre of the potato disc. Bring all the corners together and cover the filling well. If some of the filling seeps through just cover with a little more potato to coat. Roll the balls in the plain flour, followed by the egg mix and then finally the breadcrumbs, making sure to cover all sides. Now dip it in the egg mix again finally followed by the breadcrumbs. Chill in the fridge for 30 minutes.
Heat the oil in a deep-fat fryer to 180°C. Cook the fritters in batches of three or four for about 2-3 minutes, until golden brown and hot all the way through. Drain on kitchen paper while you fry the remaining. Leave to cool slightly before serving with brown sauce.