Line the base of a baking tray with greaseproof paper and lightly brush the insides with butter.
Place the flour, sugar and yeast into a bowl and stir to combine, make a well in the center.
Pour the milk, extract, lemon zest, egg, egg yolk, salt and 100 grams / 3.5 ounces of the melted butter into a separate bowl and whisk to combine.
Pour the wet ingredients into dry ingredients and stir to form a dough with a wooden spoon.
Turn onto a very lightly floured surface and knead until the dough is smooth and elastic and springs back when you push your finger into it, approximately 5 minutes.
Brush 1 teaspoon amount of the melted butter around the base of your bowl and place the dough in the center.
Cover with a damp tea towel and allow to rise in a warm place for 1 hour or until doubled in size.
Punch the dough down in the center with your fist and turn onto a lightly floured surface.
Knead until smooth and elastic, approximately 3 minutes.
Roll out the dough into a 32 centimeter / 12 inch square, approximately ? inch thick and cut into even 8 centimeter / 3.1 inch squares.
Place 1 pieces of dough in the parlm of your hand, making sure it is centered in the palm of your hand.
Spoon 1 teaspoonful of the plum jam in the center of the dough and press the edges of the dough between your fingers to thin out and stretch slightly until all the edges are slightly thinned out.
Bring 2 opposite edges of the dough together and pinch firmly to hold the edges together, bring one other end into the center and repeat until all the edges are pinched in the center and the dough is smooth.
Place the dough seam side down into the palm of your hand and shape lightly into a ball.
Place the bun seam side down into your prepared baking tin and repeat with the remaining dough until all the rolls are formed.
Ensure ½ inch space between each roll and brush with the remaining melted butter.
Cover with a damp tea towel in a warm place until doubled in size, approximately 40 minutes.
Meanwhile, preheat the oven to 190C/375F.
Place in the oven and bake for 40 minutes or until golden.
Allow to cool to warm, dust with confectioner’s sugar and serve.
Enjoy!