In a measuring cup, combine the roasted chicken base with water and mix well. Set aside.

In a medium saucepan, melt unsalted butter over medium-low heat for about 2 minutes.

Add all-purpose flour to the saucepan and whisk vigorously for about 1 minute.

Gradually pour the chicken base and water mixture into the saucepan while whisking continuously.

Increase heat slightly until the gravy starts to boil gently, then reduce to low and stir for 1-2 minutes until thickened.

Stir in the deli-sliced turkey breast and heat through for about 2 minutes.

Place two slices of white bread on each plate and spoon the turkey and gravy mixture over the top.

Sprinkle chopped fresh parsley over the sandwiches if desired, then serve.