Preheat the oven to 425℉ / 218℃. Line a 12 cup muffin/cupcake pan with liners and set aside.
In a medium bowl, combine flour, baking soda, baking powder, salt, espresso powder, and chocolate chunks and whisk until completely combined.
1½ cups (180 g) (180g) all purpose flour, 2 tsp baking powder, ½ tsp baking soda, ½ tsp salt, 1 tsp espresso powder, ½ cup (100 g) chocolate chunks, or chocolate chips
In a large bowl, add ripe bananas, granulated sugar, brown sugar, eggs, sour cream, oil, and vanilla extract, and whisk until all is completely incorporated.
1½ cups (350 g) overripe bananas, mashed (around 3 large bananas), ½ cup (100 g) granulated sugar, ¼ cup (50 g) brown sugar, packed, 2 large eggs, room temperature, 2 tbsp (30 g) sour cream, ¼ cup neutral oil, 1 tsp vanilla extract
Pour the dry ingredients into the bowl of wet ingredients and mix using a spatula until just combined (don't over mix).
Scoop batter into each cupcake liner, filling to the top of the liner (see image). Top with chocolate chunks.
Bake for 7 minutes, then reduce the heat to 350℉ / 180℃ and bake for an additional 7-8 minutes, until a toothpick inserted comes out mostly clean, with a few moist crumbs. Remove from the oven and let cool for at least 5 minutes in the pan before removing. Once cooled completely, the chocolate will harden. I suggest warming it for 10 seconds when you want to eat them.