Preheat the oven to 350℉ and prepare 2 cupcake pans by lining them with paper liners or spraying them with non-stick spray. Set them aside.
In a large bowl, combine the flour, baking powder, baking soda, and salt. Set aside.
In a separate bowl, mix together the Biscoff, brown sugar, sour cream, milk, oil, egg, and vanilla until well blended and no Biscoff lumps remain.
Create a well in the dry ingredients and pour the wet ingredients into it. Stir until just combined.
Spoon the batter into the muffin liners, filling them about ¾ full.
Bake the cupcakes for 20-23 minutes, or until a toothpick inserted comes out clean. Let them cool in the pan for 5-10 minutes, then transfer to a wire cooling rack to cool completely.

In a large bowl, mix butter and Biscoff together, using a stand mixer with a paddle attachment or a hand mixer, until the mixture is creamy and well combined.
While the mixer is on low speed, slowly incorporate the powdered sugar until fully mixed, making sure to scrape the sides of the bowl as necessary.
Add vanilla extract and salt, then pour in 1 tablespoon of milk with the mixer on low speed, mixing until well combined. If needed, add 1-2 more tablespoons of milk. Gradually increase the speed to high and beat for an additional 30 seconds to 1 minute.
Apply the frosting onto completely cooled cupcakes either by piping or spreading it.

It is important to use ingredients at room temperature for both the cupcakes and the buttercream to aid in better mixing and achieve fluffier cupcakes.
After adding the dry ingredients, make sure not to overmix the cupcake batter to prevent them from sinking in the middle.
To avoid batter overflow in the oven, be mindful not to overfill your cupcake liners. Fill them approximately ¾ full.
Enhance the decorated lotus cupcakes with Biscoff cookies, crushed Biscoff cookies, or an additional drizzle of cookie butter on top.
If you intend to make these cupcakes ahead of time, bake them and store them in an airtight container once they have cooled for up to one day.
Keep it cool: Make sure your ingredients are at room temperature for extra fluffy cupcakes!
Don’t be a mixer maniac: Gently mix your batter after adding dry ingredients to avoid sad, sunken cupcakes.
Fill it right: Don’t let your cupcakes spill the beans! Fill those liners about ¾ full.
Sprinkle some magic: Get creative with toppings like Biscoff cookies or extra cookie butter for that wow factor!
Plan ahead: Bake in advance and store in an airtight container for up to a day to keep those cupcakes fresh!