Preheat a large nonstick skillet over medium heat.

Butter both sides of the bread slices generously with softened butter.

Toast two slices of bread in the skillet until golden brown and crisp, about 3 minutes total, flipping once.

Transfer the toasted bread to serving plates.

Repeat the toasting process with the remaining bread slices.

Wipe the skillet clean.

Melt 4 tablespoons of unsalted butter in the skillet over low heat.

In a bowl, whisk the eggs with salt, pepper, and chopped chives.

Pour the egg mixture into the skillet.

Cook over low heat, stirring constantly, until small, soft curds form and the eggs are creamy, about 7 minutes.

Remove the skillet from the heat and adjust seasoning with salt and pepper to taste.

Spoon the soft-scrambled eggs onto the toasted bread.

Garnish generously with finely grated bottarga and additional chopped chives.

Serve immediately.