Preheat the oven to 350 degrees F. Line 12-16 muffin tins with paper liners.To make the streusel: In a small bowl, add 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, whisk together the butter, maple syrup, vanilla, buttermilk, greek yogurt, and eggs until smooth. Add the flour, baking powder, baking soda, cinnamon, and salt, mix until just combined. Gently fold in the blueberries and blueberry jam, being careful not to over mix. Remember, you're going for a blueberry swirl look. Divide the batter among the prepared tins. Evenly sprinkle the streusel over the batter. Transfer to the oven bake for 25-30 minutes or until a toothpick inserted into the center comes out clean. Serve warm or at room temperature.