Put the oil in a frying pan on a medium heat and add the onion Cook for about 10 mins until translucent but not brown. Add the Thyme and bacon and cook for another 5 mins. Then remove from heat and allow to cook at least 10 mins

In a large bowl add the crushed crackers (they should look like bread crumbs and add the meat / pepper and salt. Then massage the meat for 3 mins it will all come together and softer. Then add the yoke and cooled onion mixture and mix all together again for about 2-3 mins.

Divide the mixture into 4 (I know my photos only 3 but I only had 400gr meat so far adjusted)

Take 1/4 of meat and make into a round about 14cm and add the cheese on top. Then pull over the sides and pick up form into and Pattie. You can slight squash down if needed. Put on some baking paper on a large plate or Tray then put into fridge for 30 mins or cover with cling film first and can keep for 48 hours. OR put into freezer bags and keep for later.