Peel off the pummelo’s thick outer skin and as much of the white pith as you can.
Cut into each membrane and release the segments and juice into a bowl.
Squeeze the remaining membrane to extract the last of the juice.
Measure out 1/4 cup of the juice.
Add the butter to the pan at a medium high setting.
Melt butter and add the ginger, stirring occasionally. Cook for about 3 to 4 minutes until the butter begins to turn a golden brown.
Stir in the flour, stirring constantly for about 1 minute.
Stir in the pummelo juice gradually, cooking until it thickens – about 1 to 2 minutes.
Add the pummelo flesh and any remaining juice, and 1/4 teaspoon each sea salt and black pepper.
Turn the sauce to the lowest setting, just to keep warm.
In a second skillet, heat the oil at a medium-high setting.
Season the scallops with the remaining salt and pepper and add them to the oiled skillet. Sear at a high heat for about 3 minutes on each side. The scallops should be browned.
Serve hot. Plate the scallops and drizzle with the ginger and pummelo sauce.