Preheat the oven to 350° F. Butter a 9-inch bundt pan.In a large bowl, whisk together the butter, maple syrup, apple butter, vanilla, and eggs until smooth. Add the flour, baking soda, cinnamon, and salt. Mix in the chocolate chips. To make the streusel. In a bowl, combine the flour, brown sugar, and cinnamon. Add the butter and use your fingers to mix the butter into the flour until a crumble forms.Spoon the batter into the prepared pan. Top evenly with the buttery streusel mix.Bake 30 minutes, or until a toothpick inserted into the center comes out clean. Let cool 5 or so minutes. Serve the cake slightly warm or at room temperature. Serve with salty honey butter spread over each piece. Trust me, make the honey butter (see notes).