Prepare the croutons by heating butter in a frying pan.

Toast bread cubes in the butter until golden brown on all sides.

Remove the croutons and drain on paper towels.

Boil water in a large pot for poaching the eggs.

Add white wine vinegar to the boiling water and create a whirlpool.

Crack eggs individually into a cup and gently drop them into the whirlpool.

Cook the eggs for about 5 minutes over low heat until poached.

Remove the poached eggs and drain on a paper towel.

Fry bacon strips until crispy.

Remove the bacon from the pan, reserving the bacon fat.

Stir Dijon mustard and remaining white wine vinegar into the bacon fat in the pan.

Whisk in olive oil to create a dressing, then add chopped chives and season.

Combine mixed greens, cherry tomatoes, bacon, and croutons on a plate.

Drizzle the bacon fat dressing over the salad.

Top the salad with a poached egg to serve.