Preheat the oven to 350 degrees F. Line muffins tins.
Next, make the streusel. In a small bowl, combine the flour, brown sugar, cinnamon, and butter. Mix together with your hands until you have a crumbly mixture. Set aside.
In a large mixing bowl, combine the butter, maple syrup, vanilla, buttermilk, greek yogurt, and eggs until smooth (you can hand whisk or use mixer). Add the flour, baking powder, cinnamon, and salt, mix until just combined. Fold in the chocolate chips.
Divide half the batter among the prepared pan. Evenly sprinkle about 1/3 of the streusel over the batter. Add the remaining batter and then top evenly with the remaining streusel.
Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean. Serve warm or at room temperature.