• Gather all the ingredients. The eggs must be at room temperature. I highly encourage you to weigh your ingredients using a kitchen scale. For weights, click the Metric button above. If you‘re using a cup measure, please follow the “fluff and sprinkle“ method: Fluff your flour with a spoon, sprinkle it into your measuring cup, and level it off. Otherwise, you may scoop more than you need.
  

To Line the Baking Pan

• Preheat the oven to 350°F (180°C). For a convection oven, reduce the cooking temperature by 25ºF (15ºC). On your work surface, place a sheet of parchment paper that‘s 13 x 16 inches (30 x 40 cm). Set a loaf baking pan on top (I use this pan that‘s 8 x 8 x 2 inches or 20 x 20 x 5 cm). Mark the four corners of the loaf pan on the paper. Fold and crease the paper on all four sides following the corner marks. Tip: Use a light-colored pan for the best outcome.
  
• Unfold the paper and cut slits up to the square‘s left and right corners. Rotate the paper and cut two slits on the opposite side. You will have four slits total. Trim off any excess flaps and place the paper in the baking pan. Secure the paper onto the edges with stainless steel clips to keep the lining from moving when you pour the batter.
  

To Prepare the Ingredients

• In a fine-mesh sieve (or sifter) over a bowl, combine 1⅔ cups all-purpose flour (plain flour), ½ tsp baking soda, ½ tsp baking powder, ½ tsp Diamond Crystal kosher salt, and sift all together.
  
• In the bowl of a stand mixer, beat ½ cup unsalted butter (softened) until creamy.
  
• Add ½ cup sugar and whisk until well blended, fluffy, and pale yellow.
  
• Add 2 large eggs (50 g each w/o shell) and beat well.
  
• Using a silicone spatula, scrape the sides and bottom of the bowl and continue beating.
  
• Add 1 Tbsp neutral oil and 1 tsp pure vanilla extract. Beat until well blended.
  
• Add 3 ripe bananas (keep one for decoration) and stir to blend with the egg mixture. I keep some small chunks. Tip: Even though eggs and butter are at room temperature, it is normal for the mixture to look slightly curdled when the mashed bananas are added. Fat and liquids don't easily mix together. However, once the flour is added, the batter will become smoother. If you don't want to see the curdled mixture, you can add a few tablespoons of the sifted flour mixture when you add the bananas.
  
• Add the flour mixture to the banana mixture and stir just until 80% blended. Add ½ cup raisins at this stage, if you‘d like to include them, and blend for 3 seconds.
  
• While the white specs of flour are still visible, remove the mixing bowl from the stand mixer. Using the silicone spatula, hand-blend the rest of the flour. This will avoid overmixing the batter.
  
• Pour the batter into the prepared pan, spreading it evenly with the silicone spatula.
  
• Slice 1 ripe banana thinly into rounds and decorate on top of the banana bread.
  
• Bake at 350°F (180°C) until a toothpick inserted into the center of the bread comes out clean, about 50–60 minutes.
  
• Take out the baking pan from the oven and let cool for 45–60 minutes. Remove the banana bread from the baking pan.
  
• Cut the banana bread in half and cut into 1-inch (2.5 cm) slices.
  

To Store

• Wrap each slice or the whole cake with plastic wrap. Store at the cool place and enjoy within 2–3 days.