Melt butter in a medium saucepan over medium heat. Whisk in flour and cook for 60 to 90 seconds until smooth and lightly bubbly.
Slowly whisk in chicken broth and milk until smooth.
Cook for 2 to 4 minutes, whisking often, until very thick and condensed. If it doesn’t thicken in under 4 minutes, increase the heat slightly.
Once thickened, stir in garlic powder and salt to taste.
Remove from heat and allow it to cool. It will continue to thicken as it cools off.
Notes
This recipe makes about 1⅓ cups, which matches a standard 10.5 ounce can.
If the soup becomes too thick, whisk in a splash of broth or milk after thickening to thin it out.
To store, refrigerate up to 4 days in a sealed jar and reheat with a splash of broth or milk until smooth.
To freeze, portion into 1-cup containers, leave a little headspace, and freeze for up to 3 months. Thaw in the fridge overnight and whisk while warming.