Dice or cut chicken breast into small cubes.
Chop veggies too if they are too large.
Finely mince shallot.
In a sauce pan, melt the butter, when hot, add minced shallot and saute till soft.
Add dice chicken and veggies, stir a bit to brown. Add 1 tsp salt and stir to mix.
Pour in 3 cups chicken broth and bring to boil, then reduce heat to simmering.
In a separate bowl, whisk 1 cup milk with 1/3 cup flour till fully mix, break any lump if exist.
Stir in this mixture into sauce pan, make sure heat is at medium low, keep checking and stirring every minute or 2 until thick.
When thick, Add ground pepper and adjust to taste then remove from heat.