Dry off your boneless turkey breast and sprinkle with salt, garlic powder, and poultry seasoning.
Place turkey breast (skin side up if there is skin) in the slowcooker and turn on low, cover with lid.
Make your gravy on the stovetop. Melt butter in a large skillet. Add flour and stir for 1 minute to make a paste.
In a glass measuring cup, combine 1 cup of broth and cornstarch. Whisk together well and set aside.
Add remaining 7 cups of broth, Better Than Bollion, and seasoning (spices). Whisk until mixed well and heat to a simmer. Let simmer for 5 minutes while whisking.
Slowly pour in the broth with cornstarch and whisk well. Remove from heat and separate out 4 cups of gravy into a sealed container for the fridge.
Pour remaining hot gravy over turkey breast in the slow cooker. Cover with lid and let cook on low 6-8 hours.
When the turkey is falling apart, remove the skin from the top and shred the turkey. Serve over mashed potatoes with extra gravy.
If your turkey is ready to shred before you are ready to serve it, just turn the slow cooker to the warm setting until you are ready to serve it.