In a microwave-safe mug, whisk together the flour, Biscoff spread, sugar, baking powder, and salt.
Add the milk, melted butter, and vanilla extract to the mug. Stir until well combined and smooth.
Microwave the mug on high for 1.5 to 2 minutes, or until the cake has risen and set in the middle.
Allow the mug cake to cool for a minute before serving.
Optionally, top with a dollop of whipped cream or a scoop of vanilla ice cream.
Notes
Make sure to adjust the cooking time based on the wattage of your microwave. Cooking times may vary, so keep an eye on the mug cake to prevent overcooking. Enjoy this indulgent Biscoff Mug Cake as a quick and satisfying dessert!