In a large pot, melt the butter over medium-high heat. Add the chopped onions and two-thirds of the celery. Sauté for about 6-7 minutes until the onions become translucent and the celery softens.

Reduce heat to medium, add the minced garlic, and stir gently for about 1 minute until fragrant.

Sprinkle in the flour, stirring continuously to coat the vegetables evenly. Cook for about 2 minutes, then gradually pour in the chicken stock while mixing. Add the bay leaves.

Bring the mixture to a simmer over medium heat for about 10 minutes, stirring occasionally.

Remove the bay leaves and use an immersion blender to puree the soup until smooth.

Stir in the remaining chopped celery pieces into the blended soup and cook for another 5 minutes until tender.

Gently stir in the heavy cream, season with salt and pepper to taste, and a splash of lemon juice if desired. Simmer for an additional minute before serving.