Preheat oven to 375 degrees.
Melt butter in cast iron skillet over medium heat. Stir in flour, onion and garlic and cook 4-5 minutes, stirring constantly. Add stock, cream, salt, pepper and thyme. Heat to boiling, stirring constantly. Boil for 1 minute, then add veggies and boil another 2 minutes before adding the ham. Remove from heat.
Unroll crescent dough and carefully press seams together and roll dough to size of skillet. Place dough on top of skillet and cut off any excess around the edges. Place in oven and cook for 30-35 minutes or until crescent dough is golden brown and cooked through.