Step 1Heat the oven to 350 degrees.
Step 2In a large bowl, whisk together the flour, sugar, baking powder, allspice, cinnamon and ground walnuts.
Step 3Mix the eggs into the dry ingredients, 1 at a time, then whisk in the milk, vinegar and olive oil. Beat just until thoroughly combined.
Step 4Transfer the batter to a greased 13-by-9-inch pan.
Step 5Bake the cake on the center rack of the oven until puffed and golden and a toothpick inserted comes out clean, 30 to 45 minutes.
Step 6Place the pan on a rack to cool slightly before slicing on the diagonal into diamond shapes.