Bring butter, egg, and milk to room temperature. Combine all ◆ ingredients and sift.
Knead the butter with a whisk. Add the sugar and mix until smooth.
Beat the egg and mix into the bowl from Step 2 in two to three batches. Mix well, then add the condensed milk to mix some more.
Now add about half of the milk and half of the powdered ingredients. Using a rubber spatula, mix lightly in cutting motion. Add the rest of the milk and powdered ingredients and mix lightly.
Then add the kuromame and mix evenly.
Line a muffin pan or mold (I used pudding cups) with parchment paper and pour in the batter. You could also top the muffins with two or three kuro-mame beans.
Bake for 25 to 30 minutes in 170℃ preheated oven. Test with a skewer. If it comes out clean, it's ready to eat.
Story Behind this Recipe
I absolutely love the combination of matcha and kuromame black beans. Here's my try on making milky and sweet muffins with condensed milk.
When heating the butter in a microwave to melt, make sure to break after heating 10 seconds, to check you aren't melting it completely. Adjust baking time to the pan or mold you're using and also to your oven.