In a bowl add warm water, sugar and yeast and stir to combine. Let sit for 10 minutes until the yeast become foamy.
Mix flour and salt in a bowl.
Add flour, salt and melted butter to the yeast mix and mix to form a dough. Knead dough for about 10 minutes until smooth and no longer sticky. This can be done in a mixer using a hook attachment.
Form dough into a ball and place in large bowl and cover loosely with cling wrap. Place in a warm place and allow to rise until doubled in size, about 45 to 60 minutes.
Mix softened butter, shredded cheddar cheese and mustard to form a paste.
Punch down dough and turn out onto the counter. Knead for 30 seconds then cut into 10 equal pieces.
Form each dough into a ball then roll to form a circle about5 ½ inch in diameter. Spread about ½ tsp cheese spread on the dough, but not on the edges. Fold in half then spread with cheese spread, then fold in half again for form a triangle. See video for technique.
Gently press the edges together then place on an ungreased baking sheet pan. Repeat and place all the butterflap on the pan about 2 inches apart.
Cover loosely with cling wrap in a warm place and allow to rise, about 30 minutes.
Remove cling wrap then place in an oven preheated to 375degrees and bake for 20 minutes. Remove from the oven and immediately brush with melted butter.
Serve warm.
