Preheat the oven to 350 degrees F. Line a 9×5-inch loaf pan with parchment paper and spray it with nonstick spray.

In a large bowl, combine the flour, sugar, baking powder, cinnamon and salt. In a small bowl, whisk together the eggs, buttermilk, oil, molasses and vanilla extract. Mix the wet ingredients into the dry, stirring just until combined. Stir in the melted butter, stirring until combined.

To make the crumble, mix together the sugar, flour, cinnamon and salt in a large bowl. Using your fingers, a fork or pastry blender, mix in the butter until it is evenly dispersed. I use my fingers and take almost a full 5 minutes to mix it in.

Pour half of the batter into the loaf pan. Add half of the crumble on top, then pour the remaining batter on top. Cover the top with the remaining crumble. bake for 55 to 60 minutes until the top is golden and set. Remove the oven and let cool in the pan for 30 minutes. Remove the loaf by lifting the parchment paper out and let it cool for another hour before cutting.