Finely slice the shallots and garlic.

In a saucepan, melt butter and gently sweat off the shallots and garlic until softened.

Add the thyme and sugar to the saucepan.

Allow the sugar to cook and caramelize for 1 minute.

Pour in the red wine and port (if using) and reduce by two-thirds.

Add 2/3 of the blackberries, bay leaf, and beef stock to the saucepan.

Gently reduce the mixture by two-thirds.

Pour the sauce through a fine sieve into a clean saucepan and season with salt and pepper.

Cut the remaining blackberries in half and add them to the sauce.

Finish the sauce with a knob of butter and thicken with cornflour mixed with hot water, if desired.

Preheat the oven to 180C/160C fan/gas mark 6.

Heat a dry frying pan over moderate heat.

Place the duck breast fat side down in the pan and fry for a few minutes until golden brown.

Turn the breasts over and season the fat with salt.

Place the duck breasts in the oven and cook for 10 minutes.

Prepare your vegetables and finish your mash while the duck is cooking.

Remove the duck breasts from the oven and let them rest for 2-3 minutes.

Slice the duck breast and serve with vegetables, drizzling the blackberry sauce over the top.