1) First, make the crust. Whisk 1½ cups (188 g) all-purpose flour, 1
Tbsp. sugar, and 1½ tsp. Diamond Crystal or 1 tsp. Morton kosher salt in
a medium bowl to combine.
Cut 12 Tbsp. (1½ sticks) chilled unsalted butter into ½” pieces, add to
dry ingredients, and toss to coat and distribute.
2) Using your hands and working quickly, rub and smash butter into flat
irregular pieces (be careful not to overwork; you don’t want to soften
the butter too much.
Just make sure you smash each piece at least once. And if the butter is
getting too warm, throw the bowl in the fridge or freezer and let chill
for a bit before proceeding).
3) Drizzle ⅓ cup cold water over and mix with a rubber spatula, smashing
in butter, until dough mostly comes together—it will be dry and shaggy.
4) Now you are going to fold the dough, which will give it distinct
flaky layers when baked. Turn out onto a lightly floured surface.
Working quickly and using a rolling pin and your hands, press dough
together to form a mass.
(The dough will seem like a crumbly dry mess at first but will come
together as you fold and roll. Have faith and don’t give up.)
5) Roll dough into a rough square about ½” thick. Fold in half into a
rectangle, then once again to make a small square.
Press down on the dough with rolling pin to make it hold together. Roll
dough out once more to make a rough square about ½” thick.
Repeat folding process again, taking your time to make it neat, as this
will be your final fold.
6) Using rolling pin, gently flatten dough, rotating as needed, to make
a 6”-diameter disk.
Dust surface with more flour (go heavy; you don’t want the dough to
stick) and roll disk into a 14”-diameter circle or oval about ⅛” thick.
Brush off any excess flour with a pastry brush.
7) Fold dough in half, then in half again to make a rough triangle (this
just makes it easier to move).
Transfer to a parchment-lined baking sheet and unfold (it’s okay if
dough is a bit larger than the baking sheet). Chill while you make the
filling.
8) Place a rack in middle of oven; preheat to 375°. Peel and thinly
slice 1 large onion, then 8 garlic cloves.
9) Heat 3 Tbsp. unsalted butter in a medium skillet over medium until
foaming, about 1 minute.
Reduce heat to medium-low; add onion, garlic, and 1 tsp. Diamond Crystal
or ½ tsp. Morton salt, and stir to combine.
Cover and cook, stirring occasionally, until onion is tender and just
beginning to brown, 6–8 minutes.
10) Uncover and continue to cook, stirring occasionally and adding a
splash of water if onion begins to stick,
until golden brown in spots, about 5 minutes more. Transfer onion
mixture to a plate; reserve skillet.
11) While the onion mixture is cooking, finely grate 2 oz. Parmesan (you
should have about 2 cups). Trim 12 scallions, then thinly slice on a
steep diagonal.
This will yield striking oblique disks, but if you’re nervous about your
knife skills, simply slice crosswise.
12) Melt remaining 1 Tbsp. unsalted butter in reserved skillet (no need
to wipe it out) over medium heat.
Remove from heat and add scallions and remaining ½ tsp. Diamond Crystal
or ¼ tsp. Morton kosher salt. Toss scallions until coated in butter.
13) Now you are ready to assemble your galette! Remove dough from
refrigerator and, using a small offset spatula or spoon,
spread 2 Tbsp. Dijon mustard in a thin layer over dough, leaving a
1½”–2” border around the edges.
Scatter onion mixture over mustard and sprinkle with cheese; season with
freshly ground black pepper.
14) Cutting from edge of dough to the start of the mustard and filling,
make slits in border of galette at 2”–3” intervals
(the slits are optional but make for a more beautiful presentation).
Fold flaps up and over filling, slightly overlapping. Scatter scallions
over.
15) Bake galette until crust is deep golden brown and scallions are
lightly charred, 45–50 minutes.
(Your crust isn’t properly baked until it’s the color of a well-worn
penny. If your timer dings but the dough is pale, keep going.)
Using parchment paper, slide galette onto a cutting board and cut into
wedges.
Notes
1) Use caramelized onions and leeks instead of scallions.
2) Comments suggest recipe could use less butter.
3) Many comments suggest dish is overly salty and salt should be cut
down by half.
4) Add almond flour for a crunchier texture, reviewer ratio was 1 cup
all purpose 1/2 up almond.
5) Double the amount of folds with breaks in the freezer to really give
it the extra flakiness.
6) Sugar can be removed with little to no difference.