In a large mixing bowl, whisk together the flour, yeast, salt, sugar, and ground cardamom.
Add the mashed banana and stir to incorporate it into the dry .
Gently warm the milk and butter in a small saucepan or the microwave until the butter is melted and the mixture is lukewarm (around 100°F or 37°C (100°F)). Be careful not to make it too hot, as this can kill the yeast.
Pour the warm milk mixture into the bowl.
Mix everything with a spatula or wooden spoon until a shaggy dough forms.
Turn the dough out onto a lightly floured surface and knead for 5-7 minutes until it's smooth and elastic.
Don't worry if the dough is super sticky—that's the secret to a soft, tender crumb!
Place the dough in a lightly oiled bowl, cover with plastic wrap or a damp tea towel, and set it in a warm place to rise until doubled in size, about 1-2 hours.
Once risen, gently punch down the dough and divide it into 8 equal pieces. On a floured surface, roll each piece into a neat, tight ball.
Arrange the buns on a baking sheet lined with parchment paper, leaving at least 2 inches of space between each one.
Cover the buns with a clean tea towel and let them proof for a second time until they are puffy and nearly doubled in size, about 45-60 minutes.
Towards the end of the second proof, preheat your oven to 375°F / 190°C.
In a small bowl, whisk the egg with a pinch of salt to create an egg wash. Gently brush the tops of the plump buns with the egg wash.
Bake for 18-20 minutes, or until the buns are a deep golden brown and sound hollow when tapped on the bottom.
Let them cool on a wire rack before serving.
Enjoy warm!
Don't rush the proofing stages. Allowing the dough to fully double in size is crucial for achieving a light, airy, and fluffy texture.
