Boil the potato for 15 minutes until soft.

In a heavy-based pan, combine 1 ounce of butter and all of the cream and bring to a boil.

Slice the green onions, separating the green and white parts.

Add the white slices to the boiling liquid and cook for 1 to 2 minutes to soften.

Pass the cooked potato through a ricer or sieve to create a fine mash.

Add the mashed potato to the pan and mix everything together.

Set aside to cool.

Add the crabmeat and sliced green bits of the onion to the potato mixture and stir together.

Melt the remaining butter.

Unwrap the filo pastry and cover with a clean, damp tea towel to prevent it from drying out.

Brush melted butter over one sheet of filo pastry.

Place another sheet on top and brush again with butter.

Add a final sheet of filo.

Cut the filo sheets into 3 long strips.

Cut each strip in half across the middle.

Place a teaspoon of the crab mixture onto the bottom right-hand corner of each filo strip.

Fold the filo over to make a triangle, then fold again, rolling up the strip.

Ensure the mixture is enclosed to form a neat triangle shape, then place on a baking tray and brush with more butter.

Heat oven to 400 degrees and cook the rolls for 15 to 20 minutes until golden and crisp.

To serve, pile the parcels up on a plate or bowl.

Scatter over the extra sliced green onion, if desired.