Prepare the aromatics: In a large Dutch oven or heavy-bottomed pot, melt 3 tablespoons of butter or olive oil over medium heat. Add the diced onion, carrots, and celery. Sauté for 5-7 minutes, stirring occasionally, until the vegetables soften and become fragrant. This creates the flavor foundation for your soup.

Build the roux: Add the minced garlic and cook for 1 minute until aromatic. Sprinkle 3 tablespoons of flour over the vegetables and stir constantly for 1-2 minutes. The flour should turn a light golden color but not brown. This light roux will thicken your broth without making it heavy.

Add the liquid: Slowly pour in 4 cups of low-sodium chicken broth while stirring continuously to prevent lumps. Add 1 cup of low-fat milk and stir to combine. Bring the mixture to a gentle simmer. The broth should start to thicken slightly.

Cook the chicken (if using raw): If using raw chicken, add the cubed boneless, skinless chicken breasts directly to the simmering broth. Cook for 15-18 minutes, stirring occasionally, until the chicken is fully cooked and reaches an internal temperature of 165°F. If using pre-cooked or rotisserie chicken, simply add the shredded chicken after the broth comes to a simmer and proceed to the next step.

Season the broth: Stir in 1 tablespoon of fresh thyme (or 1 teaspoon dried), 1 teaspoon black pepper, and salt to taste. Remember that low-sodium broth needs more seasoning, so taste and adjust accordingly. Keep the broth at a gentle simmer while you prepare the dumplings.

Make the dumpling dough: In a medium bowl, whisk together 2 cups all-purpose flour, 1 tablespoon plus 1 teaspoon baking powder, 1 teaspoon salt, and 1 teaspoon black pepper. The generous amount of baking powder ensures light, fluffy dumplings.

Combine wet ingredients: In a small bowl, mix ¾ cup low-fat milk with 3 tablespoons melted butter or olive oil. Pour this mixture into the flour mixture.

Mix the dough gently: Use a wooden spoon to stir just until the ingredients come together. The dough should be slightly sticky but hold its shape. Important: Don't overmix—this is the key to tender dumplings. A few lumps are perfectly fine.

Drop the dumplings: Using a medium cookie scoop or two spoons, drop heaping tablespoons of dumpling dough directly onto the simmering broth. Space them evenly around the pot, but don't worry if they touch—they'll expand as they cook. You should get about 12-15 dumplings.

Steam the dumplings: Place the lid on your pot immediately and reduce heat to low. Let the dumplings steam for 15-18 minutes without lifting the lid. This trapped steam is what makes the dumplings fluffy and light. Resist the urge to peek!

Check for doneness: After 15 minutes, carefully remove the lid. The dumplings should have doubled in size and appear dry on top. Cut one in half to check—it should be cooked through with no raw dough in the center. If needed, cover and cook for an additional 3-5 minutes.

Rest and serve: Remove from heat and let the pot sit uncovered for 5 minutes. This allows the dumplings to firm up slightly and the broth to thicken to the perfect consistency. Serve hot in bowls, making sure each serving gets plenty of chicken, vegetables, and fluffy dumplings.