Step 1

Pour 1/2 cup of bran cereal into a small bowl. Cover with boiling water, stir, then set aside to cool.

Step 2

Meanwhile, whisk the flour, sugar, baking soda, baking powder, and salt in a large bowl. Then, mix in the raisins and stir until they're well coated in the flour mixture.

Step 3

When the bran mixture is cool, mix in the vegetable oil and egg.

Step 4

In a separate bowl, whisk the buttermilk, brown sugar, vanilla, and cinnamon.

Step 5

Pour the buttermilk mixture into the flour bowl and gently stir. Then, add the remaining 1 1/2 cups of dry bran cereal, the softened bran cereal, and the walnuts.

Step 6

Mix the batter until combined, cover the bowl, and refrigerate it overnight.

Step 7

When ready to bake, preheat the oven to 375 degrees Fahrenheit (190°C) and line a muffin tin with muffin liners. Spray them lightly with cooking spray. Or, for a crusty muffin exterior, grease the muffin cups directly.

Step 8

Take the batter out of the fridge and stir once or twice. Then, scoop 1/4 cup of batter into each muffin cup.

Step 9

Bake for 20 to 25 minutes or until a toothpick inserted into the center comes out clean.

Step 10

Let the muffins cool in the pan for 10 minutes, and then transfer them onto a wire rack to cool completely. Serve and enjoy!