In a pressure cooker, add turkey leg and 1 cup of chicken stock and pressure cook for 1 hour. Alternatively, boil on the stove until tender and falling off the bone. Set turkey meat and any remaining stock aside.
To a medium saucepan on medium heat, melt butter and add in flour. Stir consistently to create a blonde color roux.
Add in onions and cook for 1 minute or until transclucent and follow with garlic. Cook until fragrant, stirring frequently.
Slowly add in stock and stir until roux is dissolved. Lower heat to medium low, and allow a few minutes to thicken.
Add in potatoes and all purpose seasoning. Simmer covered for 15-20 minutes until fork tender.
Add in rinsed green beans and rosemary, and stir into gravy. Cover for 8 minutes, stirring occasionally, until green beans are semi-tender.
Remove from heat, and serve alongside your favorite thanksgiving dishes.