Melt 2 tablespoons butter in a cooking pot.
When the butter is hot, add ham. Cook for 1 minute.
Put-in potato, onion, and celery. Cook for 1 to 2 minutes.
Pour-in chicken broth. Let boil. Simmer for 15 minutes.
Meanwhile, melt the remaining butter in a saucepan.
Gradually whisk-in flour. Stir until the mixture thickens.
Slowly pour milk while continuously stirring. Cook (while stirring) until the texture becomes thick. Set aside.
Pour the milk and flour mixture on the cooking pot where the ham and potatoes are. Add salt and pepper. Stir and simmer for 5 to 8 minutes.
Transfer to a bowl and garnish with spring onion.
Serve. Share and enjoy!