Heat oven to 350°F. Line 12 muffin cups with paper liners or spray with cooking spray. Beat butter and 1 cup Sugar In The Raw® in large bowl. Beat in eggs and milk. Add flour, cocoa, baking powder and salt; beat on LOW just until mixed. Stir in chia seeds. Batter will be thick.
Divide among muffin cups. Sprinkle tops with Sugar In The Raw®. Bake 30 to 35 minutes until toothpick inserted in center comes out clean. Cool in pan 5 minutes; remove to wire rack.