Soften butter with a potato masher or something similar. Spread the butter on waxed paper to an 8 by 16-inch rectangle. Chill.
Dissolve yeast in the warm water. Add milk, sugar, salt, lemon extract, and egg and mix well. Add flour and mix smooth by hand. A nice dough should be formed Wrap with plastic wrap and chill.
Roll the dough on well-floured board to an 8 by 12-inch rectangle. Divide the prepared butter layer into 2 equal parts. Place 1 piece of the butter on 2/3 of the dough. Fold the uncovered third of dough over the middle third (on top 1/2 of the butter layer), then fold the remaining third over the top. Chill.
Roll dough again to an 8 by 12-inch rectangle. Place the remaining piece of chilled butter on 2/3 of the dough. Fold in the same method as the first piece of butter.
Gently roll dough to an 8 by 16-inch rectangle being careful not to break the layering of butter. Fold like above in thirds. This make 24 layers of butter. Chill.
Cut the dough into 2 equal pieces. Lightly and patiently roll 1 piece at a time, until piece is about 6 by 20 inches.
To prepare filling mix ingredient until smooth. Spread center third of dough with butterscotch filling, then add fruit, nuts, raisins or jam. Fold 1 of the long edges to the middle, moisten other edge and fold over top to cover filling. Seal well.
Put kringle on lightly greased baking sheet and form into oval shape, pressing ends of kringle together to form a continuous oval. Flatten entire oval with hands. Cover kringle for 1 hour at room temperature.
Preheat the oven to 350 degrees F.
Bake for about 20 to 25 minutes, until golden brown color. Cool, then ice with mixture of powder sugar and water.
Please note that the best quality kringle require patience. This process is most successful when spread out over three days. Day 1, roll in first piece of butter. Day 2, roll in second piece of butter and additional fold. Day 3, create your kringle or other fine Danish pastries. A quality Danish pastry should be light, tender, flaky, and full of flavor. With patience and pride this recipe will yield just that.