Preheat the oven to 350℉. Line a standard loaf pan (approx. 9 x 5 inch) with parchment paper, leave a bit of overhang to be able to pull the loaf out of the pan later.
In the mixing bowl of a stand mixer, cream the butter and sugar.
Mash the bananas with a fork until evenly mashed (see notes). Add them to the batter. Add the eggs and vanilla. Mix until just blended.
In a separate bowl, whisk together flour, baking soda, and cardamom. Add to the batter. Mix until just blended. Scrape down the sides and bottom of the bowl with a rubber spatula and briefly mix again to incorporate.
Pour the batter into the loaf pan. Bake for 55-60 minutes or until a toothpick or thin knife inserted into the center comes out clean or with just a scant amount or batter. Allow the loaf to rest 10 minutes before lifting out onto a cooling rack. Let the loaf cool for 1 hour before slicing.
Notes
Mashing bananas: The goal is to create a consistent, puree-like consistency for a moist texture, or slight chunks for a more rustic, cake-like loaf.Salted butter: salted butter works perfectly requiring no additional salt in the recipe. If you use unsalted butter, add 1/2 tsp of salt to the recipe (whisk into the flour mixture).Let it cool: Waiting matters! Cooling allows the bread to finish "setting." Cutting it when it is too hot often results in a compromised texture because the steam hasn't fully escaped. A cooled loaf will also slice better, whereas warm bread will tend to tear or crumble under a knife.