Pre-heat oven to 350 degrees or 325 degrees convection.
Line a baking sheet with parchment paper. Tip: Use a little bit of butter or cooking spray to keep the sheet in place.
Add flour to a medium sized bowl.
Cube butter and add to bowl with flour. With a pastry cutter or fork, cut butter into flour until all of the butter is well combined. You'll know it's cut in well when you can easily form 2 evenly sized rough balls of dough and it all sticks together.
Add each dough ball to the cookie sheet. Use your hands to form each pile of dough into a long flat strip approximately 12 inches long and 3 inches wide. Set aside.
Make Choux
Add water and butter to a small to medium sized saucepan and heat on medium and bring water to a boil while the butter melts. Be sure to watch the water so that it does not boil over. If it does, you will need to start again.
Once boiling, add the 1 cup of flour and almond extract to the pan and turn down heat to low. Use a fork to vigorously stir in flour until a ball of dough forms and beings to pull away from the side of the pan. Approximately 1 minute.
Remove pan from heat. Add 1 egg to the pan and with your fork beat it very very fast into the dough. Be sure that you do this quickly so that the egg does not scramble. Repeat with all eggs, continuing to beat vigorously, until you have a smooth velvety dough. Set aside to cool for about 10-15 minutes.
Make Frosting
While choux cools, in a medium sized bowl add softened butter and almond extract. Use a hand mixer to cream butter. Slowly add 3/4 cup of powdered sugar and beat together until the butter and sugar is a soft and creamy frosting. Set aside.
Assembling
Once choux has cooled, scoop it out onto the shortcrust. Do this one even sized scoop at a time, alternating between each crust to assure an even split.
Use a spoon, spatula, or your hands to smooth the layer of choux on each shortcrust into a flat layer that covers the top of the crust.
Add to oven and bake for 1 hr.
After 1 hr the pastry should be golden brown and dry.
Remove pastries from oven and gently transfer to a cooling rack and store in a draft free space of your kitchen for at least 30 minutes. If there is a draft, your pastry will sink.
Final Assembly
Once pastry is cool, split frosting in two and frost the top of each in an even layer.
Top with sliced almonds and halved maraceino cherries, if desired.
Slice into strips and serve!
Video
Notes
Storage: Fridge: Cover and store in a fridge for up to 1 week. Freezer: You can store the cooked danish puff, unfrosted, in the freezer for up to 1 month. Let thaw completely and then frost before serving. Substitutions:Butter: Use unsalted butter and add 1/4 teaspoon of fine ground salt to your shortcrust flour and another 1/4 teaspoon to your choux flour. Give each a quick mix before continuing with the recipe.Extract: You can use vanilla extract in place of the almond flavor in the choux and/or the frosting. Shortcrust Tips: See the Step-by-Step Instructions section in the above post. Choux Tips: See the Step-by-Step Instructions section in the above post.