Open and rinse the scallops if you use fresh shells.
If you use frozen scallops, leave them to defrost in the fridge before use, then drain on paper towel.
Make square patterns on one side with a sharp knife, to make sure the scallops get fried evenly.
Peel the potatoes and remove the bitter layer under the peel. Cut in chunks and boil in water until tender. Pass the potatoes through a sieve.
Melt about one-third of the butter in a pot and add finely chopped garlic. Add the potatoes and mash until smooth.
Add the remaining butter and season with salt and pepper. Keep the purée warm until serving.
Put the coriander in a food processor. Slowly add the oil.
Mix until smooth, for around two minutes. The oil can be stored in a sealed bottle in the fridge for up to three weeks.
Fry the coriander seeds in a dry frying pan on high heat to extract flavour, then crush in a mortar. Season the scallops with the seeds, salt and pepper.
Finely chop garlic and chili. Heat butter and oil in a frying pan until light brown, then add garlic and chili.
Fry the scallops for about 30 seconds on each side – no longer as this will give them a rubbery texture. Pour over butter while frying.
Put two scallops and a slice of lime on each skewer.
Serve the skewers with the coriander oil and sweet potato purée on the side. Garnish with fresh coriander.
Tip: You can also grill the scallop-skewers.