Preheat your oven to 350°F (180°C). Butter and line a 5x9-inch (13 x 23 cm) loaf pan with a strip of parchment paper.
Mix the flour, baking soda, baking powder, cinnamon, and salt in a medium bowl and set it aside.
In a mixing bowl, mix the butter, vegetable oil, and sugar until creamy. Add the eggs one by one, then toss in some vanilla and mix.
Slowly add the flour mixture while the mixer's running on low. Alternate with the buttermilk until everything is mixed. Fold in semi-sweet chocolate chips.
Pour half your cake batter into the 5 x 9 loaf pan. Mix cinnamon and sugar in a small bowl, then sprinkle half of that mix on top of the batter.
Pour in the rest of the cake batter. Top it off with the remaining half of the cinnamon sugar mixture. Bake for 40 to 45 minutes. If the top is browning too fast, drape foil over it.
Doneness test: Stick a small toothpick in the middle. The toothpick should be clean when pulled out.
Set the whole pan on a cooling rack to rest (5 to 10 minutes). Then, take the cake out of the loaf pan and let it cool completely at room temperature. Enjoy your delicious cake.