Preheat the oven to 120°C.
Simmer Madeira, port, shallot, brandy, thyme, and garlic in a pan until onions soften.
Add chicken livers and cook for 2 to 3 minutes.
Blend livers and liquid in a food processor, gradually adding eggs and butter until smooth.
Pass the mixture through a fine sieve into a bowl.
Divide parfait into four ramekins and place in a roasting tin.
Fill the tin with boiling water halfway up the ramekins and cover with foil.
Bake in the oven for 20 to 25 minutes.
Dissolve sugar in vinegar over heat, add sliced beetroot, and simmer for 2 minutes.
Drain beetroot, season with salt and pepper, mix with mint, and set aside.
Remove parfaits from the oven and allow to cool.
Soften gelatine in cold water, then dissolve in beetroot juice with 50ml boiling water.
Pour gelatine mixture over parfaits and refrigerate until set.
Serve with toasted sourdough and the pickled beetroot.