Step 1: Prepare the Topping - In a small bowl, mix together 3/4 cup of all-purpose flour, 1/2 cup of packed brown sugar, and 1 teaspoon of cinnamon. Add the cubed cold butter and mix with a fork or pastry cutter until crumbly. Set aside.
Step 2: Mix Wet Ingredients - In a large mixing bowl, whisk together 1/2 cup of melted butter, 1/2 cup of real maple syrup, and 2 teaspoons of vanilla extract. Add 1/2 cup of buttermilk, 1/2 cup of plain Greek yogurt, and 2 eggs, and mix until smooth.
Step 3: Combine Dry Ingredients - In another bowl, combine 2 cups of all-purpose flour, 2 1/2 teaspoons of baking powder, 1/2 teaspoon of cinnamon, and 1/2 teaspoon of kosher salt. Whisk to combine.
Step 4: Bring It All Together - Gradually add the dry ingredients to the wet mixture, stirring gently until just combined. Be careful not to overmix! Fold in 1 cup of semi-sweet chocolate chips until evenly distributed.
Step 5: Fill Muffin Tin - Preheat your oven to 350°F (175°C). Line your muffin tin with paper liners or grease it lightly. Fill each muffin cup about two-thirds full with the batter. Sprinkle the topping mixture generously over each muffin.
Step 6: Bake - Bake for about 18-20 minutes or until a toothpick inserted into the center comes out clean. The tops should be golden and slightly domed.
Step 7: Cool and Serve - Once baked, remove the muffins from the oven and let them cool in the pan for about 5 minutes, then transfer them to a cooling rack. Enjoy warm or at room temperature with your favorite coffee or tea!