Masterchef Dr. Tim Kinnaird breaksdown how to make choux pastry.
3 1/2 oz. butter
1/2 cup milk
1/2 cup water
2 pinches of salt
1/2 oz. superfine sugar
5 oz. all-purpose flour (or 50/50 all-purpose/strong white breadmaking flour)
4 medium eggs, plus extra for glazing.
Step 1: Make sure all your ingredients are at room temperature. Warm the butter in a pot with milk, water, salt and sugar. Ensure the liquid doesn't boil until the butter is melted. Once all the butter is melted, bring to the boil for 10 seconds.
Step 2: Remove the pot from the heat and add the flour in one go. Stir slowly to start with to enusre the flour doesn't spill out of the pot, then as the past comes together, return to a medium heat and cook, stirring all the time. The paste needs to come together as one ball, but it also needs to develop a slight shine or gloss to its surface. This takes 30 to 60 seconds of beating on the heat.
Step 3: Tip the paste into a clean bowl or the bowl of a free-standing mixer and beat for 30 seconds. This cools the paste a little and releases steam. Continue to beat the past and add the eggs a little at a time. Ensure the paste is smooth and well combined before adding the next amount of egg. The exact amount of egg required will vary. The final pastry needs to be smooth, glossy and easily piped, but it also needs to be thick enough to support itself. If too much egg is added the pastry will spread after piping, producing flattened and poorly risen choux. A good way to judge if you have added enough egg is to lift the pastry from the bowl on a large spoon spatula. The pastry should adhere well to the spatula but then fall back into the bowl with a clean snap. If too little egg is added the pastry won't adhere to the spatula at all; if too much egg is added the pastry will adhere but then quickly run back into the bowl, dripping off the spatula.
Step 4: Preheat the oven to 300°F and place an empty metal baking tray in the bottom of the oven. Piping still warm choux pastry is one of baking's greatest pleasures. Using a piping bag is the best way to shape the pastry for basking, and using a template is a great way of producing uniformly shaped and sized choux buns. Specialist choux pastry silicone trays are also available. Fit a piping bag with a plain or fluted nozzle approximately 1" in diameter. Holding the nozzle slightly above the parchment or tray and at a 45° angle, pipe 6" lengths of pastry. It helps to stop squeezing the piping bag 1/2" - 1" from the end of the eclair and gently flick the end of the nozzle in the opposite direction, cleanly finishing each eclair. Another technique is to pipe long strips of pastry on a baking sheet and freeze them.* Once frozen, the pastry may be cut into precise 6" lengths. Allow the pastry to defrost completely before baking. Once piped, brush the pastry with egg wash to give a glossy finish.
Step 5: Pour 2 cups of warm water into the baking tray on the bottom of the oven. This creates steam and a humid environment to help the pastry rise. Bake the pastry in the preheated oven for 1 hour. Do not be tempted to open the door to check on them for at least 45 minutes. The drop in temperature and humidity will cause the pastry to collapse. After 1 hour, check the pastry. The shells should sound hollow when tapped and be an even golden color. If not, return them to the oven and bake for a further 5 - 10 minutes.
* Choux pastry freezes remarkably well. Shaped, unbaked pastry may be frozen for up to a month. Ensure the pastry is completely defrosted before baking. The shells may also be frozen after baking. Defrosting and refreshing them in the oven at 350°F for 3 - 4 minutes returns them to their original fresh, crisp form.
Reprinted with permission from Perfect Patisserie: Mastering Macarons, Madeleines and More (2013 Firefly Books Ltd.)