Originally from allrecipes.com. I put mine in the slow cooker in the morning. Watch the potatoes, they may get too soft. Leave the butter/flour/milk combo until about a half our or so before serving. I used evaporated milk because I read someone sometimes had problems with milk curdling in their crockpot. I didn't want to risk it so I've never tried it.
3 1/2 cups peeled and diced potatoes
1/3 cup diced celery
1/3 cup finely chopped onion
3/4 cup diced cooked ham
3 1/4 cups water
2 tablespoons chicken bouillon granules
1/2 teaspoon salt, or to taste
1 teaspoon ground white or black pepper, or to taste
5 tablespoons butter
5 tablespoons all-purpose flour
2 cups milk
1. Combine the potatoes, celery, onion, ham and water in a stockpot. Bring to a boil, then cook over medium heat until potatoes are tender, about 10 to 15 minutes.
2. Stir in the chicken bouillon, salt and pepper.
3. In a separate saucepan, melt butter over medium-low heat.
4. Whisk in flour with a fork, and cook, stirring constantly until thick, about 1 minute.
5. Slowly stir in milk as not to allow lumps to form until all of the milk has been added.
6. Continue stirring over medium-low heat until thick, 4 to 5 minutes.
7. Stir the milk mixture into the stockpot, and cook soup until heated through.