In a large bowl, whisk together flour, thyme, salt, paprika, black pepper, ginger, allspice, and red pepper. Reserve 2 tablespoons flour mixture. Add steak tips to remaining mixture, stirring to coat.
In a 10-inch cast-iron skillet, heat oil over medium-high heat. Add onion and steak tips; cook, stirring frequently, until onions are tender and steak is browned on all sides, 8 to 10 minutes. Add garlic; cook until fragrant, about 1 minute. Stir in reserved flour mixture; cook for 1 minute. Stir in broth until smooth. Add sweet potatoes, and bring to a boil. Reduce heat to medium-low; simmer until potatoes are fork tender, about 20 minutes. Stir in kale until wilted; remove from heat.
On a lightly floured surface, unfold dough, and tuck corners under. Roll into a circle; carefully place dough over skillet. Crimp as desired. Brush with egg, and sprinkle with more black pepper, if desired.
Bake until golden brown, 15 to 18 minutes. Let cool for 5 minutes before serving. Garnish with thyme, if desired.
Recipe by Southern Cast Iron at https://www.southerncastiron.com/steak-and-sweet-potato-pie/