Wash Brussels sprouts in cold water. Trim off any spotted or bruised leaves. Cut sprouts in 1/2, trimming off bottom of cores as needed. Set aside.

Cut off the root and green portion of the leeks. Cut remaining white part of leek in 1/2 lengthwise. Gently peel apart the leek at the root end. Wash well with cold water to remove sand. Dice leeks into 1/2-inch squares. Set aside.

Wash carrots with cold water. Gently scrape or peel to clean the exterior. Trim greens to 1 inch in length. Set aside.

In a large saucepot, add water, salt and sugar.

Set pot over high heat and bring water to a boil.

Prepare an ice bath by placing a dozen large ice cubes in a large bowl. Add water to fill about 1/2-way up the sides. Set aside.

Once water has come to a boil, place Brussels sprouts in the water to blanch for 3 minutes. Remove with a slotted spoon or spider strainer and immediately place in prepared ice bath. Shock 1 minute in an ice bath. Immediately remove and drain in a colander. Do not leave in ice water for more than 1 minute or they will become soggy.

Blanch carrots 4 minutes. Remove from boiling water using a slotted spoon or spider strainer. Drain in the colander. Place in a single layer on a sheet pan and place in refrigerator to cool.

Add pancetta to a cold sauté pan.

Place pan over medium heat.

As pancetta cools and gives off grease, increase heat to medium-high. Cook, stirring occasionally, until pancetta is golden brown and bottom of pan is coated with golden fat.

Reduce heat and remove pancetta from pan with a slotted spoon. Set aside on a paper towel-covered plate.

Add leeks to pan in which pancetta was cooked. Cook over medium heat, stirring frequently, until leeks become translucent but not brown, about 2 minutes.

Add reserved carrots. Cook, stirring frequently, 2 minutes.

Add reserved Brussels sprouts. Cook an additional 3 minutes or until hot.

Add reserved pancetta and butter. Stir well. Cook for 30 seconds.

Remove from heat.

Taste. Season with salt and pepper, to taste.

Serve immediately.