Heat the oven to 200C/180C fan/gas 6. Scrub and trim the carrots, and cut them in half lengthways or into quarters if large. Toss the carrots with 1 tbsp olive oil and 2 tbsp maple syrup in a bowl. Season well, and tip onto a baking tray. Roast for 20-25 mins until tender and starting to caramelise.
Meanwhile, mix the flaxseed with 4 tbsp water and leave to thicken. Heat 1 tbsp olive oil in a frying pan, and fry the onion and celery until soft and translucent, about 10 mins. Add a splash of water if you need to, to stop them from catching. Stir in the garlic, mushrooms, rosemary, tomato purée, tamari and paprika, and fry for another 10 mins until the mushrooms are tender. Remove from the heat and leave in a bowl to cool slightly.
Put the pecans and hazelnuts in a food processor and blitz until roughly chopped. Add the lentils and chickpeas and blend again until you get a thick, dry paste.
Combine the nuts and pulses, mushroom mixture, ground almonds, 2 tbsp maple syrup and soaked flaxseed in a bowl with a good amount of seasoning. Mix everything well using your hands.
Oil six holes of a mini loaf tin and line each with a strip of baking parchment. Trim and cut the carrots to fit in the base in a snug single layer, cut-side down. Roughly chop any remaining carrots and mix them through the nut roast mixture. Pack it firmly into the tins and smooth over. Bake, uncovered, for 20 mins. Leave to rest for 10 mins before inverting onto a serving plate, or plates. Fry the sage and thyme in the remaining 1 tbsp olive oil until crisp, then stir through the remaining 1 tbsp maple syrup. Spoon over the nut roasts to serve.