Preheat oven to 400°F (200°C). Grease a 7 1/2 x 3 x 2 inch loaf pan.

In a bowl, combine milk and breadcrumbs. Stir and set aside to soften.

In another bowl, beat egg yolks until thick and lemon-colored.

Add the breadcrumb mixture, lemon juice, salt, and pepper to the egg yolks. Stir to combine.

Add the drained, flaked salmon to the mixture. Stir gently to combine.

In a separate clean bowl, beat egg whites until stiff peaks form.

Gently fold the beaten egg whites into the salmon mixture until just combined. Be careful not to overmix.

Spoon the salmon mixture into the prepared loaf pan.

Bake for 35 minutes, or until golden brown and cooked through.

While the loaf is baking, prepare the white sauce.

Melt butter in a saucepan over low heat.

Add flour to the melted butter and stir until smooth. Cook for 1 minute, stirring constantly.

Gradually pour in the milk, stirring constantly to prevent lumps.

Cook over medium heat, stirring constantly, until the sauce thickens and becomes bubbly.

Season the white sauce with salt and pepper to taste.

Once the salmon loaf is cooked, let it cool slightly before slicing.

Cut the salmon loaf into slices and serve with the warm white sauce on top.