Preheat oven to 350°. Spray a 7-well cast-iron mini cake pan with baking spray with flour.
For topping: In a medium bowl, whisk together flour, pecan pieces, granulated sugar, ground pecans, orange zest, and salt. Stir in melted butter until mixture is crumbly. Press mixture with your fingertips to form clumps as desired.
For cake: In a large bowl, whisk together sugar, melted butter, egg, orange zest and juice, and vanilla. Whisk in flour, ground pecans, baking powder, and salt until combined. Whisk in sour cream and milk until combined. Fold in pecan pieces. Divide batter among wells of prepared pan, smoothing tops. Sprinkle topping onto batter.
Bake until a wooden pick inserted in center comes out clean, 25 to 30 minutes. Let cool in pan on a wire rack for 15 minutes. Remove cakes from pan.
For glaze: In a small bowl, whisk together confectioners’ sugar and orange juice until smooth. Drizzle onto cakes. Garnish with zest strips, if desired.
Recipe by Southern Cast Iron at https://southerncastiron.com/orange-pecan-mini-coffee-cakes/