Combine all the dry ingredients of the pastry and put them into a food processor.

Using cold butter, chop it up into small squares and add it to your food processor also. Pulse the dough together until crumbly, adding 1 Tbsp. ice water until the correct consistency.

Chill your dough in the freezer for 10 minutes.

Roll the dough out between 2 silpats using a rolling pin. Cut out circles using a cookie cutter or a glass.

Put the dough into your whoopie pan and preheat your oven to 325F.

Prep all the filling ingredients - chop spring onions, mince garlic, and slice mushrooms.

Saute onions and garlic in olive oil. Add ground beef to the mixture and sear it well - adding dry spices and Worcestershire.

Add mushrooms and mix together. Then add tomato paste and mustard right before finishing.

Spoon ground beef mixture evenly into the pastry tartlets. Cover with cheese and bake for 20-25 minutes.

Optional: Broil for 3-5 minutes before taking out the oven.

Let cool completely and remove the pastries.