The amount of ham and cheese inside these croissants might seem a tad skimpy, but resist the urge to add more. The extra moisture from the filling can make the interior soggy and affect how the dough rises, so rest assured it’s more than enough to flavour these savoury pastries.

You'll need a batch of croissant dough, from this series' lead recipe, rolled out to a 38-by-40-cm slab, and chilled. (For the dough, follow the croissants recipe through to step 16.)

1 Arrange racks in the upper third and lower thirds of the oven. Bring a cast-iron frying pan of water to a simmer over medium-high heat. Transfer the pan to the floor of the oven and close the door. (The steam released inside the oven will create an ideal proving environment for the pastries.) Line two rimmed baking sheets with parchment paper and set aside.

2 Let the dough sit for 5 minutes at room temperature. Unwrap (save the plastic wrap for proving) and place on a very lightly floured surface. If the dough has shrunk during chilling, roll it out again to a slab that's 40cm long and 38cm wide. Dust off any excess flour.

3 Use a wheel cutter to trim 1cm of dough from all four sides, straightening and squaring them off, creating a slab that's 38cm long by 35cm wide. Using a ruler, cut the slab lengthwise into 5 equal strips each measuring 7cm wide. Cut each strip in half crosswise, creating 10 rectangles.

4 Working with one rectangle of dough at a time, cover one half with a slice of ham, folding it as needed to leave a 1cm border along the short side. Then top with 2 tablespoons of the cheese. Roll the dough into a snug spiral, starting at the end with the ham and cheese, then transfer the spiral to one of the prepared baking sheets, resting it on the seam. Repeat with the remaining dough, ham and cheese, dividing between the sheets and spacing evenly. Very loosely cover with plastic wrap so the pastries have some room to expand.

5 Open the oven and stick your hand inside: it should be humid but not hot, as the water in the pan will have cooled. You want the pastries to proof at 21 to 23 degrees. (Any hotter and the butter will melt, leading to a denser pastry.) Gently place the baking sheets inside the oven on the two racks and let the pastries prove until they have doubled in size, are extremely puffy and jiggle delicately on the baking sheet, 2 to 2½ hours.

6 When the pastries are proved, remove the baking sheets from the oven and carefully uncover them. Transfer to the refrigerator and chill for 20 minutes while you heat the oven. Remove the pan from the oven and heat the oven to 190 degrees.

7 In a small bowl, stir the yolks and double cream until streak-free. Remove the baking sheets from the refrigerator and use a pastry brush to gently brush the surfaces of each pastry with the yolk mixture. Transfer the sheets to the oven and bake for 20 minutes. Rotate the baking sheets and switch racks and continue to bake until the pastries are deeply browned, another 10 to 15 minutes. Remove from the oven and let cool completely on the baking sheets.

The pastries are best within an hour or two of baking. After that, revive them by warming in a 170-degree oven for 5 to 8 minutes. Keep wrapped airtight at room temperature. – New York Times

This recipe is from a series
Introduction: How to make stunning croissants at home
Recipe: Croissants
Recipe: Pain au chocolat
Recipe: Almond croissants