Using the bowl of a food blender, add the milk and the yeast together and slowly mix.
Crack in the 2 free range eggs into the bowl and mix again.
Carefully pour the flour, sugar and ½tsp of fine sea salt into the bowl and thoroughly mix for about 5 minutes until fully combined.
Whilst the food mixer in still running add a little of the butter and leave to be mixed.
Keep doing this until all of the butter has been incorporated.
In a clean large non metallic bowl, oil the sides with the flavour free oil (rapeseed etc.)
Pour the dough mixture into the oiled bowl and cover with a clean tea towel/cloth. Put to one side in a warm area and allow to prove for ideally 2 hours. It should double in size.
Lightly flour your worksurface so the dough doesn't stick.
Transfer the dough onto the floured surface and divide into 12 portions. Roll each one into a tight ball and place onto a lightly dusted tray. Leave space between each one as they will grow.
When all have been rolled, cover with a cloth and allow to prove again until doubled in size.
In a wide deep sided pan add about a third deep of oil and heat to 180C. Alternatively you can use a deep fat fryer but I would recommended using fresh oil.
Place a few pieces of kitchen paper on a large plate to help drain any excess oil.
In a separate bowl combine the cinnamon and caster sugar and mix together.
Cook the doughnuts, in batches using either the deep pan or dee fat fryer. Cook for 1-2 minutes each side. Flip when it has a lovely golden colour.
Carefully remove the donuts with a slotted spoon and place on the kitchen paper to drain.
When slightly cooled but still warm, roll the donuts in the cinnamon and sugar mixture and place on a wire rack to finish cooling.
Finally pour the seedless jam into a bowl and whisk to thin it out. When thin, pour into a piping bag with a a fine nozzle.
Use a skewer or ice pick to make a small hole in the donut but dont go all the way through.
Gently push the nozzle into the hole and pipe some jam in. This will be trial and error but as to how much to enjoy.