Melt butter, sugar, and water in saucepan on the stove.
Bring to a boil while stirring.
Remove from heat and stir in only 2 cups of the chips.
Let cool a bit.
Stir in one egg at a time.
Add vanilla.
Stir in dry ingredients and the 1 cup chips.
Pour in 9x13 pan lined with nonstick foil.
bake at 325 for 40 minutes.
Let cool.