Preheat the slow cooker if necessary; see the manufacturer's instructions. Liberally butter the inside of 4 heatproof china ramekin dishes, each 150 ml (¼ pint), and break an egg into each ramekin.
Drizzle the cream over the eggs and sprinkle over the herbs and a little salt and pepper. Transfer the ramekins to the slow cooker pot and pour boiling water into the pot to come halfway up the sides of the ramekins.
Cover with the lid (there is no need to cover the dishes with foil) and cook on high for 40–45 minutes or until the egg whites are set and the yolks still slightly soft.
Lift the dishes carefully out of the slow cooker pot with a tea towel, transfer to plates and serve with smoked salmon, lemon wedges and triangles of toast.