Preheat the oven to 400° F. Spray a rimmed baking pan (jelly roll pan) with nonstick spray or line with parchment.
In a medium saucepan, combine the water, butter, sugar and salt. Bring to a boil over medium-high heat.
Add the flour all at once. Beat with a wooden spoon until the mixture forms a ball. Remove from heat and let cool for 2 minutes.
Transfer the dough to a food processor. Add the eggs one at a time, processing until eggs are fully incorporated. Mix in the lemon zest.
Divide the dough in half and form each half into a 3x15-inch rectangle on the prepared baking sheet (space them at least 3 inches apart). Bake 30 minutes, until puffed and golden.
PREPARE THE ICING:
In a small saucepan, heat the milk, butter, vanilla, lemon juice and almond extract over medium-low heat. Whisk in 1 cup of the sugar; add remaining sugar as needed until icing reaches drizzling consistency.
Drizzle icing decoratively over cakes. Sprinkle with almonds and serve.