Heat the oil in a large saucepan over a medium heat. Add the garlic, chopped fennel seeds and thyme and cook for 1 minute. Add the onion, celery and carrot and cook for 15 minutes until soft. Remove from the pan and allow to cool slightly.
Place the pork and the cooked vegetable mix in a large bowl and add the breadcrumbs. Season well and mix with your hands until really well combined.
Heat the oven to 200C/180C fan/Gas 6. Roll out the puff pastry to a large rectangle approx 30cm x 40cm to the thickness of a pound coin then cut in half lengthways.
Divide the sausage mixture into two and place in a log shape down the centre of each pastry rectangle. Brush one edge with the egg then fold the other side over and press firmly to enclose the log tightly. Slice each log into 15 diagonal rolls then transfer to the baking trays seam side down. Brush the pastry with a little egg and sprinkle with fennel seeds.
Place in the oven reduce the temp to 190C/170C fan/Gas 5 and bake for 25 minutes until golden brown.
2tbsp olive oil
3 garlic cloves, crushed
20g (3/4 oz) fennel seeds, finely chopped, plus some whole for sprinkling
2tbsp thyme leaves
1 onion, finely chopped
2 celery sticks, finely chopped
1 large carrot, finely chopped
500g (1lb10 oz) minced pork
20g (3/4 oz) dry breadcrumbs
500g (1lb10 oz) puff pastry
1 egg, lightly beaten