Preheat oven to 425. Place rack in center of oven. Line standard muffin pan with paper liners. Set aside.
In a large bowl, whisk together flour, baking powder, cinnamon and salt. Set aside.
In a medium bowl, whisk together brown sugar, milk, vegetable oil, eggs, and vanilla until well combined.
Add wet ingredients to dry ingredients and mix until combined and no flour streaks remain. Fold in the 3/4 cup of the chocolate chips.
Divide batter evenly among muffin cups, filling each 3/4 full, Top batter with remaining 1/4 cup chocolate chips, a few in each cup.
Bake for 5 minutes at 425, then reduce the oven temperature to 350. Bake for an additional 13 ;minutes or until tester inserted in center comes out with just a crumb or two.
Cool in pain for 10 minutes, repeat with remaining batter and chocolate chips.