In a food processor, pulse flour, sugar, salt, yeast and cardamom until well combined.
Add cubed butter and pulse until butter pieces are the size of large peas.
In a medium bowl, whisk together milk, water, egg, and vanilla.
Pour flour and butter mixture into a large mixing bowl. Add liquid ingredients and gently blend together until a dough forms. Dough will be rough looking.
On a lightly floured work surface, roll dough into an 8 x 18” rectangle. Place slices of butter side-by-side in the center of the dough.
Fold one short edge of dough over the butter and fold the other short edge on top as if folding a letter and enclosing the sliced butter.
Roll dough into a large rectangle about 10 x 18” and 1/8 inch thick.
Fold the 2 shorter edges in, to meet in the middle. Now fold in half as if closing a book.
Repeat rolling dough out to a 10 x 18” rectangle, and do a book fold as in step 8.
Repeat rolling dough out, and do one last book fold.
At this stage, the dough can be wrapped in plastic wrap and allowed to rest in the refrigerator for about 30 minutes to one hour or left overnight.