Let’s get baking! Here’s a detailed, step-by-step guide:

Step 1: Prepare Baking Sheet and Preheat Oven

Gather all ingredients, and preheat the oven to 425 degrees F (220 degrees C). Line a baking sheet with a silicone liner (such as Silpat®) or parchment paper.

Step 2: Make Choux Pastry Base

Combine the butter, Irish stout beer, salt, and sugar in a saucepan over medium-high heat.

Let the butter melt completely and bring the mixture to a simmer.

Step 3: Add Flour

Add the flour all at once to the simmering liquid.

Stir vigorously with a wooden spoon until the mixture comes together and forms a smooth dough, about 30 seconds.

Step 4: Dry Out Dough

Continue to cook and stir the dough until it dries out a bit and starts sticking to the bottom of the pan, another minute or so.

Step 5: Cool Dough Slightly

Turn off the heat and continue stirring for another 1 to 2 minutes, scraping as much of the dough off the bottom of the pan as you can. This helps to cool the dough slightly before adding the eggs.

Step 6: Incorporate Eggs

Transfer the dough to a bowl.

Add one egg and whisk it vigorously into a bit of the hot dough to temper the egg. Then, continue whisking in the rest of the dough until the egg is fully incorporated. The dough will look separated at first, but it will come together as you whisk.

Repeat with the remaining egg, cleaning out the whisk as needed, until well combined and the dough is sticky and smooth.

Step 7: Add Cheese and Cayenne

Add 3/4 cup of the grated Irish Cheddar cheese and the pinch of cayenne pepper to the dough.

Stir until the cheese and cayenne are evenly incorporated.

Step 8: Form Puffs

Scoop 12 rounded tablespoons of dough onto the prepared baking sheet, spacing them evenly apart.

Press a little extra shredded Cheddar cheese on the tops and sides of each puff.

Step 9: Bake

Bake in the center of the preheated oven until the cheese puffs are nicely puffed and beautifully browned, about 25 minutes.

Step 10: Cool

Turn off the oven and crack the oven door open. Let the cheese puffs cool, undisturbed, for 30 minutes. This helps to prevent them from collapsing.

Step 11: Make Leek and Mascarpone Spread

While the cheese puffs are baking and cooling, make the spread. Heat the olive oil in a pan over medium heat.

Add the chopped leeks and 1/2 teaspoon of salt. Cook and stir until the leeks are just barely tender, 7 to 10 minutes, adding a splash of water every few minutes to prevent browning. The leeks should be softened but not browned.

Stir in the sliced green onions and sauté briefly for 1 to 2 minutes.

Transfer the leek-onion mixture to a bowl and let it cool for 5 to 10 minutes.

Step 12: Finish Spread

Add the lemon juice and mascarpone cheese to the cooled leek mixture.

Mix until well combined.

Season with salt and freshly ground black pepper to taste. Refrigerate until the cheese puffs have finished cooling.

Step 13: Serve

Serve the cooled Irish Beer Cheese Puffs with the leek and mascarpone spread.

Enjoy this delicious and sophisticated appetizer!