Combine water, sugar, and yeast in a large bowl to make dough. Let rest about 5 minutes, until foamy.

Add 2 cups flour, 1 tablespoon melted butter, and salt to mixture. Stir with wooden spoon until dough forms. Will be very wet and sticky.

Sprinkle remaining flour on work surface. Knead the dough on the floured surface, folding in excess flour as needed until dough is soft, elastic, and only slightly sticky.

Place dough into a greased bowl, cover, and allow to sit in warm place until volume has doubled. Approximately 1-1/2 hours.

Mix together sugar and a portion of the sea salt in a bowl. Add more salt to taste.

Grease muffin tin with remaining belted butter. Spoon the sugar mixture into each cup and shake to coat. Pour excess sugar mixture back into the bowl.

Move dough onto floured surface and roll dough into a rectangle about 1/8"-1/4" thick. Grate 1 stick of butter onto dough, leaving 1" border clear.

Flatten butter into dough with floured hands. Fold dough into thirds, place onto a silicon lined baking sheet.

Wrap in plastic and place in refrigerator for 30 minutes.

Roll dough into a large rectangle and grate remaining stick of butter onto dough. Pat down and fold dough into thirds.

Roll dough into a rectangle and fold into thirds two more times, without grating any more butter.

Wrap in plastic and refrigerate for 1 hour.

Preheat oven to 375°F.

Sprinkle seasoned sugar onto work surface. Place dough onto sugar mixture and sprinkle more mixture on top of dough. Roll into a large rectangle (last time) 1/8"-1/4" thick, turning the dough and topping with more sugar between rolls.

Use a pizza cutter to clean up uneven edges. Cut dough into 12 equal squares. Sprinkle more sugar mixture on top. Lightly pinch together the corners of each square and place into prepared muffin tin.

Sprinkle more sugar mixture on top and let rest for 10 minutes.

Bake in oven until puffed and brown, approximately 25-30 minutes. While hot, transfer pastries to cooling rack. Allow to sit for 15 minutes before serving.