First Step: Prepare Ingredients Chop the onion finely and mince the garlic if using. Shred the cooked chicken breast and dice the ham. Soften cream cheese by leaving it at room temperature. Measure out butter, flour, chicken broth, half-and-half, and shredded cheese.

Second Step: Sauté Aromatics In a large pot, melt 1/4 cup butter over medium heat. Add diced onion and sauté until soft and translucent, 2 to 3 minutes. Add minced garlic and cook an additional 30 seconds for aroma.

Third Step: Create Roux and Add Broth Sprinkle 1/4 cup flour over the butter and onion mixture, stirring constantly for 1 to 2 minutes to create a light roux. Gradually whisk in 3 cups chicken broth, stirring continuously to avoid lumps. Bring to a gentle boil while stirring often, cooking 1 to 2 minutes until slightly thickened.

Fourth Step: Add Cream Cheese and Half-and-Half Reduce heat to low. Add softened cream cheese, stirring until fully melted and smooth. Pour in 2 cups half-and-half (or substitute blend of heavy cream and milk) and stir to combine.

Fifth Step: Incorporate Cheese and Proteins Add shredded Swiss cheese, stirring continuously until melted and silky. Stir in shredded chicken, diced ham, and mustard if using. Heat gently until warmed through, about 5 minutes.

Sixth Step: Season and Add Fresh Herbs Taste the soup and season with salt and pepper to preference. Stir in chopped parsley for freshness and color, if desired.

Final Step: Serve and Garnish Ladle hot chicken cordon bleu soup into bowls. Garnish with croutons, toasted breadcrumbs, or serve in bread bowls for texture contrast and presentation. Enjoy immediately for the best flavor and creamy consistency.