You will need a 6-cup (or larger) muffin tin and a baking sheet for this recipe.
Prepare the dough: In a large bowl or the bowl of a stand mixer fitted with the kneading hook, add the lukewarm water, yeast and sugar. Stir to combine. Add the melted butter, salt and flour. Knead 4-5 minutes, adding a bit more flour, only if necessary, until you have a smooth dough that cleans the bowl. Form dough into a ball, place into a greased bowl and allow to rise until doubled, about 90 minutes.
Meanwhile, prepare the filling by stirring together the brown sugar, white sugar, cinnamon, orange zest and salt. Set aside.
Remove dough to a floured surface and gently deflate. Divide into 3 equal portions (I like to weigh the dough ball first, then divide by 3 and weigh out equal sized portions. For this bake, my individual balls were 99g. Yours may be slightly different.) Form the dough into 3 balls and cover with a clean tea towel. Leave to rest 10-15 minutes.
Take one ball of dough and place on a lightly floured surface. Begin rolling into a long oval shape, rolling until it is roughly 18-22 inches and is very thin (you should be able to see through it). Spread the entire surface with soft butter, then sprinkle evenly with about 2 1/2 Tbsp of the cinnamon sugar mixture. Starting from the far short end, roll up tightly (see Step-by-Step photos above this Recipe Card). Using a sharp knife, cut down the centre of the log, cutting it into two pieces. Place one piece with the cut side up and coil it up, tucking the tail end underneath and pushing up slightly from underneath, to pop the top up a bit. Place into a muffin cup. Repeat with remaining dough until you have 6 cruffins. Cover with plastic wrap and allow to rise about two hours.
*You can refrigerate at this point overnight, if you want to bake them in the morning. Next day, remove from the refrigerator and allow to stand at room temperature about 2 1/2 hours before baking.
Preheat oven to 390F (not convection bake). Place muffin tin on top of a baking sheet to catch any butter that may bubble out while it cooks. Bake 22-25 minutes, or until golden. Remove from oven and allow to cool in the muffin tin for about 5 minutes. Run a knife around the outside and gently lift onto a cooling rack to cool further or completely. Serve dusted with confectioners' sugar.
Be sure to have a look at the Step-by-Step photos above this Recipe Card, for a visual summary of making these cruffins that you may find helpful to see the process of shaping them. You will also find some additional Baker's Tips there, as well.