Wash and cut the potatoes into bite-size pieces. Add to a pot of boiling water and cook until fork tender, about 5-8 minutes. Be careful not to over-cook them--you don't want them to be too soft. Drain into a colander and set aside.
In the same pot, over medium heat, add the butter and melt. Stir in flour and cook for 1 minute, stirring constantly.
Slowly stir in milk, whisking the entire time, until blended and smooth. Cook, stirring, until slightly thickened. Add the chicken bullion paste and season with pepper and a little bit of salt.
Stir in heavy cream until you've reached a good gravy consistency.
Taste the sauce, and add more salt, pepper or bullion paste, as needed to reach a great flavor. Add another splash of milk, if needed, to thin the mixture.
Add potatoes and frozen peas and stir everything gently to coat. Serve warm.
