Add flour, salt, sugar and softened butter to a food processor, process until combined. Add the cold butter, pulse until just combined, you will still be able to see some larger pieces of butter, this will create flakey layers.

Pulse in the beer until completely incorporated into the dough. Dough will be very soft.

Lay a long sheet of plastic wrap on a flat surface, add the dough to the center.

Form into a flat disk. Wrap disk tightly in plastic wrap. Chill until firm, about 3 hours and up to three days.

In a large bowl add the blackberries sprinkle with 2 tablespoons sugar, cornstarch, lemon zest, lemon juice. Toss to coat. Allow to sit while you prepare the dough.

Knead the dough lightly in hands until dough comes together and warms slightly. Roll out on a lightly floured pieces of parchment paper to form a large circle, about ¼ inch thick. Transfer the dough circle and the parchment paper to a baking sheet.

Pour off any liquid that has accumulated in the blackberry bowl.

Add blackberries to the center of the galette.

Fold the bare edges of the dough up over the filling, using the parchment paper if necessary.

Preheat oven to 400.

Transfer the baking sheet to the freezer, freeze for 15 minutes. Alternately you can chill in the fridge for 30-45 minutes (or overnight). This will help the galette stay together when baking and help the crust to be lighter and flakier.

Brush the crust with melted butter, sprinkle with remaining sugar.

Bake at 400 for 30-35 minutes or until crust is golden brown. Allow to cool prior to serving.