1. Prepare for Baking:

Gather all ingredients.

Preheat the oven to 425 degrees F (220 degrees C).

Line a baking sheet with a silicone liner (such as Silpat) or parchment paper.

2. Make the 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.

3. Add Flour and Cook:

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.

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.

4. Cool Slightly and Add Eggs:

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

Transfer the dough to a bowl.

Add one egg and whisk it into a bit of the hot dough. Keep whisking in more dough until the egg is fully incorporated.

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

5. Incorporate Cheese and Cayenne:

Add ¾ 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.

6. Form the 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.

7. Bake and Cool:

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

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.

8. Make the 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 ½ 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.

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.

9. Finish the Spread: Add the lemon juice and mascarpone cheese to the cooled leek mixture.

Mix until well combined.

Season the spread with salt and freshly ground black pepper to taste.

Refrigerate the spread until the cheese puffs have finished cooling.

10. Serve:

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