Make the Batter: Beat together the vegetable oil and sugar in a large mixing bowl with an electric mixer just until combined, about 30 seconds. Add the eggs and mix on medium high speed for 30 seconds, until well combined. Add the mashed banana, vanilla, and milk and mix until just combined. Mix in the dry ingredients until just a few flecks of flour are visible. Toss the chocolate chips with 1 tsp of flour, then fold into the batter with a spatula or wooden spoon.
1/3 cup vegetable oil, 1 cup granulated sugar , 2 large eggs, at room temperature , 1/2 tsp vanilla extract, 1/3 cup milk, at room temperature , 1 and 3/4 cups all-purpose flour, spooned & leveled or weighed out, 1 tsp baking soda, 1/4 tsp baking powder, 1/2 tsp salt, 1/4 tsp cinnamon, 1 cup chocolate chips + more for topping