Working ahead, make and chill crust. In a large bowl, whisk together the flours, sugar, and sea salt. Use a large hole, coarse grater to grate in the butter. Use your fingertips to blend butter into the flour. Using a silicone spatula, drizzle water over the mixture, using just enough flour so the dough easily holds together. Divide dough into two equal discs, flatten, cover with plastic wrap, and chill for at least 30 minutes or up to 5 days.