In a mixing bowl, combine the 450 grams Plain Flour & the 7½ tsp Baking Powder (yes this is the correct amount - for UK Self-raising flour, only add 2 tsp baking powder). 'Cut in the butter' till rough large breadcrumb consistency. DO NOT USE A FOOD PROCESSOR- use 2 butter knives, a Pastry Cutter/Pastry Blender or your fingertips. ***Please see the step-by-step instructions & photos before this recipe card for more information or watch the video,
Add the 50 grams Caster Sugar (US Extra/Super fine sugar) Lemon Zest, mix to combine then leave to the side. Crack the 2 Med-Large Eggs into a jug & top up with approximately 240 ml Milk, until you get to the 300ml (10 fl oz, 1¼ cup level). Add the 1 tsp Lemon Extract & whisk together, before reserving 2 tbsp in a small dish for egg-wash.
Make a well in the flour mixture before adding ½ the egg mixture & mixing with a spoon, pushing down to make the flour take on as much liquid as possible. Add ⅓ of the blueberries, (if using frozen, remove from the freezer now and coat in the sugar & flour). Gently fold the blueberries in, then repeat with the remaining blueberries. Very gradually add in more liquid until the mixture comes together and is only slightly sticky. You might not need all the liquid or a little more milk. (See video for reference).
Flour a work area or some baking/parchment paper, form the dough into a ball & pat out on the paper, using your hands. DO NOT USE A ROLLING PIN. Pat it out with your hands, to a thickness of at least 1" (2½cm).
Dip the straight edge of the cookie cutter in flour before cutting out your scones. DO NOT TWIST THE CUTTER. You will get about 5 - 6 scones from the first round. Scones that lift up, shake onto the prepared paper. Those scones that stick, just leave to the end. Pull back the excess dough, then carefully transfer with a palette knife (try not to touch the sides).
When all 4 or 5 scones are in the air fryer basket (on top of the paper), very carefully brush the reserved egg-wash on the top of the scones. DO NOT LET IT DRIP DOWN THE SIDES. Tap the brush of excess egg-wash & start to brush from the centre outwards.