Bundt Cake:

1. Preheat oven to 180C/325F.

2. Butter grease and dust with flour a 24cm Bundt pan.

3. In a medium bowl, whisk together, flour, crushed Biscoff biscuits, baking powder and baking soda.

4. In a large bowl, add the sugar and butter. Beat on medium spread until light and fluffy.

5. Add the eggs one at a time, beating well after each addition.

6. On low speed, add a 1/3 of the dry ingredients and mix until combined. Slowly add half of the buttermilk and mix until incorporated.

7. Continue alternating the flour and buttermilk until it has all been incorporated. 

8. Pour half of the batter into your prepared bundt pan. Drizzle the 1/2 cup melted Biscoff spread (cool if hot) over the cake batter.

9. Pour in remaining batter and bake for 45-50 minutes.

10. Cool for 20 minutes in the pan then invert onto a cooling rack to cool completely. 

Topping:

1. Slightly heat the remaining Biscoff spread in the microwave. Leave to cool if it is hot and pour over cake.

2. Leave the spread to dry and set before topping with white chocolate.

3. Melt the white chocolate in the microwave and stir in the vegetable oil. (The vegetable oil added to the chocolate will keep is soft).

4. Pour into a piping bag. Snip off the tip of the piping bag and drizzle over the Biscoff spread. 

5. Top with crushed Biscoff biscuits.