In a frying pan heat a glug of olive oil and fry the fennel seeds for around 60 seconds.
Add the chopped onion and mushrooms and on high heat, stirring until brown (approx 10mins). Once done, tip into a large bowl with the sausagemeat and chopped dill.Season and mix altogether.
With your ready-rolled puff pastry, roll onto a board and place your sausagemeat lengthways down the middle of the pastry.Next cut strips into the pastry, coming out from the sausagemeat all the way down.Finally, cross the strips in a lattice over the sausagemeat to cover it.
Transfer the sauasge roll onto a baking tray lined wih ba aking sheet lined, brush with the beaten egg, then bake for 30-35 minutes.
Notes
TOP TIP: Avoid a soggy bottom!Once it's on the oven tray (before you place in the oven), pop the tray over a hob on medium-high to cook the pastry bottom for a few minutes.