Preheat oven to 375 degrees F (190 degrees C).

Cut bread into 1-inch cubes and place in a small bowl.

Pour milk over bread and let soak for 5 minutes.

Heat olive oil in a large skillet over medium heat.

Add chopped onion, celery, and minced garlic to the skillet.

Cook until vegetables are soft and translucent, about 3-5 minutes.

Remove from heat and let cool for 5 minutes.

In a large mixing bowl, combine grated carrots, soaked bread mixture, ground sirloin, ground pork, eggs, chopped parsley, Dijon mustard, salt, and pepper.

Add the cooled onion mixture to the bowl.

Mix all ingredients well using your hands or a rubber scraper.

Place mixture in an ungreased baking dish or roasting pan.

Shape the mixture into a 5x12 inch loaf.

Overlap bacon slices across the top of the meatloaf, covering it completely.

Arrange scrubbed fingerling potatoes and halved, rinsed leeks around the meatloaf in the baking dish.

Season the potatoes and leeks with salt and pepper to taste.

In a small bowl, combine packed light-brown sugar, ground mustard, and 2 tablespoons of water.

Stir in tomato paste to create a glaze.

Brush the meatloaf all over with the glaze.

Bake in the preheated oven, brushing with glaze every 15 minutes, until juices run clear when the loaf is pierced with a two-pronged fork and the bacon is crisp, approximately 1 hour and 15 minutes.

Let the meatloaf cool for 10 minutes before slicing.

Serve with the potatoes and leeks on the side.