Preheat the oven to 180°C (350°F). Grease and flour one 7-inch bundt pan, or grease and line one 8-inch loaf pan.

Place 150 g butter and 150 g granulated sugar in a mixing bowl. Beat until the mixture is pale, light, and fluffy.

Add 1.5 teaspoons vanilla extract to the creamed mixture. Beat briefly until combined.

Add the 3 eggs one at a time. Beat well after each addition until fully incorporated.

Sift 150 g all-purpose flour and 1.5 teaspoons baking powder into a second mixing bowl. Whisk the dry ingredients together.

Fold one-third of the dry ingredients into the egg mixture. Fold in part of the 60 ml milk.

Repeat the folding process with the remaining dry ingredients and milk. Stop folding as soon as a thick, smooth batter forms.

Fold 8 to 10 crushed Biscoff biscuits into the batter, if using. Avoid overmixing the batter.

Transfer the batter to the prepared bundt pan. Smooth the surface evenly with a rubber spatula.

Bake at 180°C (350°F) for 40 to 45 minutes. Test the center with a skewer; it is done when the skewer comes out clean.

Cool the cake in the pan for 10 minutes. Invert it onto a cooling rack and cool completely.

Warm 60 g Biscoff spread until pourable. Whisk it with 60 g powdered sugar to make a thick glaze.

Drizzle the Biscoff glaze over the cooled cake. Let the glaze set before slicing and serving.