In a large Dutch oven, melt the butter and saute the onions, celery, carrots, and bell pepper over medium heat, stirring frequently, for 15 minutes or until tender.
Add the garlic, asparagus tips, and green peas and continue to cook a few more minutes until asparagus is tender.
Turn heat down to low, add the flour, an cook, stirring constantly, for 2 minutes. Add the broth and simmer for 1 more minute, stirring until it thickens to about the consistency of a cream soup. Add salt, pepper, thyme, cream, turkey meat, and kale. (The mixture may seem too runny but will thicken as it bakes)
Transfer mixture to a casserole dish *(I used a medium sized dish - approx 8x11", but a 9x13 is fine too). Set aside until ready to top with pastry crust.* Note: If using a double crust, set mixture aside until bottom crust has been placed in pan.
Preheat oven to 375 degrees while you start on the pastry.