Before you start, preheat your oven 175 °C (347 °F) and line a 7x3" (18x7.5cm) loaf pan with baking paper. Crack 2 eggs into a jug and add 20 ml whole milk and 2-3 drops vanilla essence. Whisk until combined and set aside.
Sift 100 g cake flour and 1 tbsp matcha powder together into a bowl and whisk. Scoop out 1 tbsp and save it in a small bowl for later. Add ½ tsp baking powder and 1 pinch salt to the bowl and mix.
In a separate bowl, whip 100 g butter and 100 g granulated sugar together until pale and smooth. Gradually add the egg mixture while whisking.
Add the dry ingredients to the wet ingredients one-third at a time and whisk until smooth and there are no more lumps of dry flour. Be careful not to over-mix.
Pour 100 g boiled adzuki beans into a separate bowl and pat them with kitchen paper to remove excess moisture. Add the tablespoon of matcha flour from earlier and toss until evenly coated to help prevent sinking.
Mix the flour-dusted adzuki beans into the cake batter until evenly distributed.
Pour the batter into the lined loaf pan and bake for 40-50 minutes at 175 °C (347 °F) or until a skewer comes out clean or with just a few moist crumbs.
Cool in the pan for a few minutes then remove and finish cooling on a wire rack. Once cool enough to touch, slice and enjoy!
Notes
Store at room temperature in an airtight container for 1-2 days, or in the fridge for 4-5 days. For longer storage, wrap and freeze in a sealable bag or container for 1-2 months.For the most consistent results, weigh ingredients on scales rather than using cup measures.Bring all ingredients to room temperature for easy mixing. Make sure the butter is soft, but not melted, before you start the recipe.Sub adzuki beans with chocolate chips, dried fruits or nuts.