In the large bowl, whisk together the flour and salt. Add the chilled cubed butter and shortening; cut the butter and shortening into the flour mixture using your fingers, two knives, or a pastry blender until broken down into pea-sized pieces. Add the egg yolk and the sage and mix until combined. Gradually add the cold water and mix until the dough comes together. If it’s crumbly, add a bit more water 1 teaspoon at a time. If it seems sticky, add a bit more flour.