Gather the ingredients. With the rack in the middle position, preheat the oven to 350°F (180°C).In a medium mixing bowl, combine the 225 g all-purpose flour, 1 tsp. baking soda, 1 tsp. baking powder, and ½ tsp. salt. Whisk to combine and set aside.
In a large mixing bowl, cream the softened 115 g unsalted butter and 210 g sugar together with an electric mixer until light and fluffy.
Add the 1 egg and 1 tsp. vanilla extract and beat until the mixture is smooth.
For the best possible flavor, toast the 150 g walnuts or pecans before adding them to the batter. You can do this by spreading them on a baking sheet and baking for 5-7 minutes at 350°F (180°C) until they are fragrant.
Let them cool completely before chopping and adding them to your batter.
In the same bowl, mash the ripe 3-4 ripe bananas. Stir the 120 g sour cream and 150 g walnuts or pecans into the mashed bananas.
At low speed, add the dry ingredients to the mixture. Mix only until just combined. Do not overmix.
The Baking
Butter a loaf pan and line it with a strip of parchment paper, letting the excess hang over the two longer sides.
Pour the batter into the prepared loaf pan and spread evenly.
Bake for about 1 hour, or until a toothpick inserted into the center of the bread comes out clean.
Let the bread cool in the pan on a wire rack for at least 10 minutes before using the parchment paper sling to remove it from the pan. Let cool completely on the wire rack before slicing.
The Serving
Serve your Mom's Banana Bread [Мамино банановый хлеб] with a nice cup of fresh coffee or tea.