These muffins feature a luscious center of moist, rich cinnamon filling. Add a confectioners' sugar glaze once they're cool, if you like, but they're really just as good with simply their streusel topping. Bonus: our Baker's Cinnamon Filling makes these muffins a cinch to pull together.
Preheat your oven to 400°F. Line a 12-cup muffin pan with cupcake papers, or grease it lightly.
To make the topping: In a small bowl, mix together all the ingredients together until crumbly. Set aside.
To make the filling: In another small bowl, mix together the Baker's Cinnamon Filling and enough water to make a soft, pudding-like consistency. If you're using the substitute, simply mix together all of the ingredients and set aside for 15 minutes to thicken.
To make the batter: In a bowl or large measuring cup, whisk together the melted butter, milk, and eggs.
In a separate bowl, whisk together the dry ingredients, including the chips.
Add the liquid mixture to the dry ingredients, stirring just until combined.
Divide half the batter evenly among the muffin cups; a tablespoon cookie scoop, generously filled, works well here.
Dollop 2 teaspoons of the filling onto each muffin; a teaspoon cookie scoop, filled level, works well here.
Top with the remaining batter.
Sprinkle generously with the topping, pressing it in lightly.
To bake the muffins: Bake for 20 to 25 minutes or until the tops of the muffins are golden brown.
Remove the muffins from the oven, and wait 5 minutes before transferring them from the pan to a rack to cool.
To make the glaze: In a small bowl (re-use the bowl that had the topping in it to reduce clean up), mix the glaze ingredients together until smooth. Drizzle over the cooled muffins and serve warm, or cool a rack and then enjoy.
Storage information: Store leftover muffins in an airtight container for a day or so at room temperature, or for several days in the refrigerator. Freeze, well wrapped, for longer storage.
Don't have Baker's Cinnamon Filling mix? Substitute 3 tablespoons (42g) melted butter, 1/2 cup (106g) light or dark brown sugar, and 2 to 4 teaspoons cinnamon for the Baker's Cinnamon Filling mix and water. (Use the lesser amount for stronger cinnamons, like Vietnamese (Saigon); the larger amount for milder cinnamons, like Indonesian/Ceylon.) Important: Be sure to omit the listed water! Use only butter, sugar, and cinnamon. Let the mixture sit for 15 minutes before using, to thicken.
