Unroll the puff pastry sheets, placing them on pieces of fresh parchment paper. Cover each one with a second piece of parchment and roll each pastry sheet out to a square shape, approximately 8 x 8 inches (20 x 20 cm).

Lift up the top parchment papers and sprinkle the surface of both pastries with 2 tablespoons (30 mL) each of white sugar. Place the parchment back on top and roll lightly to press sugar into the dough.

Remove top parchment papers again and fold the bottom third of the dough up towards the centre, then fold the top third down towards the centre (as though folding a letter to prepare it for an envelope).

Rotate the dough on your work surface 90 degrees then replace the top parchment sheets and roll each sheet of puff pastry out to an 8 x 8 square once again.

Repeat steps 2, 3 and 4 to add a second helping of sugar to each pastry sheet. Lay the parchment-enclosed pastry sheets on a baking tray and refrigerate for 30 minutes.

While dough is resting, generously grease 8 compartments of a muffin tin with the butter.

To assemble the pastries, remove dough from the fridge and lift it off the bottom parchment sheets. Sprinkle a little bit more sugar (about 1 teaspoon/5 mL) on the bottom parchment, then replace the dough. Remove the top parchment and sprinkle the tops of the dough with 1 teaspoon (5 mL) of sugar. If the dough has shrunk a little, replace the top parchment and roll back out to a square slightly larger than 8 x 8 inches (20 x 20 cm).

With a very sharp knife or a pizza cutter, square up the sheets of dough by trimming edges then cut each one in half lengthwise to create two strips approximately 4" x 8". Cut each strip into two 4" x 4" squares, making 8 squares in total.

Lift up each pastry square and fold the four corners toward the center to create the distinctive crown shape of the kouign amann then gently nestle the pastries into the greased muffin tin compartments.

Cover the muffin pan with plastic wrap and refrigerate overnight if desired. When ready to bake, leave the muffin tin on the counter while the oven preheats to 400F. Just before baking, sprinkle the tops of the pastries with the salt, if using.

Put the pastries in the centre of the preheated oven and reduce heat to 375F. Bake for 35 – 40 minutes, rotating pan halfway through baking, until pastries are golden brown and sugary edges are nice and caramelized.

Remove tray from oven and immediately transfer pastries to a serving plate (they’ll stick to the tin like crazy if you don’t do this). Let cool 2 minutes or longer before devouring. Leftovers can be stored at room temperature in an airtight container for up to 2 days.