Thaw bread dough. Drizzle olive oil on a baking sheet then roll dough into an oval shape and place on baking sheet. Poke fingers down into dough making dimples in the dough, brush with melted butter. Place in preheated oven for 5 minutes. Remove and spread caramelized onions over flatbread, place apple slices evenly over onions, sprinkle with cheddar cheese. Combine salt and rosemary in the palm of your hand and sprinkle evenly over the flatbread.
Bake in 450 degree oven for 12-15 minutes or until cheese is bubbling and starting to brown. Remove and drizzle a teaspoon of olive oil over flatbread and sprinkle with chopped walnuts. Cut into small pieces and serve!