Recipe makes around 20 cruffins

For the croissant dough:

3 tbsp unsalted butter
1 3/4 cups whole milk
4 tsp instant or rapid-rise yeast
4 1/4 cups (21 1/4 oz or 602g) all-purpose flour (King Arthur preferred)
1/4 cup (1 3/4 oz or 50g) sugar
2 teaspoons kosher salt

For the butter layer:

12 oz (24 tbsp) unsalted European-style-butter, cold (european butter recommended)

DAY ONE

1. Melt the butter in a small saucepan over low heat. Remove from the pan and immediately add the milk. Whisk in the instant yeast and transfer the entire mixture to the bowl of a stand mixer fitted with the dough hook attachment.
2. Add the flour, sugar, and salt to the bowl. Knead on low speed for 2-3 minutes until a dough forms. Increase the speed to medium-low and knead for another minute.
3. Flour a pie dish or flat plate and drop in the dough. Use your fingers to spread the dough out slightly. Cover with plastic wrap and refrigerate for 6 hours or overnight.

DAY TWO

4. Fold a 24 inch of parchment paper in half lengthwise. It will look like a book cover.
5. On all the three open ends of the paper, fold the loose ends inwards to create an 8 inch square. Make sure all sides are sealed. I started with the two sides opposite one another and then did the last one.
6. Remove butter from the fridge. Unfold your parchment square. Place your butter on top of one of the sides of the 8 inch square. I like to cut the butter in 1/2 inch slices and place them next to each other to form a square shape inside the parameter of the square. Fold the sides over again to seal the butter inside and flip the packet so the loose ends are on the bottom. Use a rolling pin to roll out the butter to one smooth 8 inch slab. Return the butter to the fridge for another 30 minutes to harden up.
7. After 30 minutes, remove the dough from the refrigerator. Deflate it slightly with your fingertips and flour your work surface. Turn the dough out onto the work surface and use a rolling pin to shape the dough into a 10×10 inch square.
8. Take the butter slab from the fridge and unwrap it from the parchment paper. Place the slab in the center of the dough, but at an angle so the butter and dough look like a diamond sitting on top of a square. Make sure your butter is not too stiff that it cannot be rolled out or too soft that it will not hold its shape. Fold each corner of the dough over the butter slab and seal together in the middle so the butter is fully encased.
9. Roll out the dough into an 8×24 inch rectangle. Fold the dough into thirds and make sure to brush off any excess flour with a pastry brush. Cover in plastic wrap and return to the refrigerator for 30 minutes to allow the butter to harden again.
10. After 30 minutes, remove the dough from the refrigerator. Turn the dough 90 degrees so the longer side of the dough is vertical to you. Roll the dough out to another 8×24 inch rectangle and fold into thirds. Return to the fridge for 30 minutes. Repeat this step (turn, roll, fold) again one more time. After all three turns, cover the dough with plastic wrap and place it back in the fridge to rest overnight or for 24 hours maximum (overnight is best).

DAY THREE

11. The following day, remove the dough from the fridge. Cut the dough in half and place the second half back in the fridge until ready to use. Roll out the first half of the dough into a 8×15 inch rectangle.
12. Use a knife to make small cuts in 3 inch increments down the longer side of the dough. Cut the dough into 3×8 inch rectangles, then cut rectangle in half at an angle to create a triangle-like shape.
13. Roll the triangles up starting from the larger side, making sure to keep one side flat as you roll. Place the cruffin in the popover tin, flat side down. Try to place it as evenly as possible so the cruffin will be able to stand once it is baked. You can use a toothpick to help push the edges down into the tin to create a stable base. Cover the cruffins with a kitchen towel and let proof for 2-3 hours. The cruffins will not double in size but be significantly larger.
14. After proofing, preheat your oven to 400F and place a rack in the middle position. Create an egg wash by whisking one egg and a splash of milk together. Brush the egg wash on top of the cruffins. Bake them for 20-25 minutes until completely browned.

For the Matcha Pastry Cream:

1/2 cup caster sugar
1/4 cup cornstarch
pinch of salt
2 cups whole milk, room temperature
4 egg yolks, room temperature
2 tsp matcha powder, sifted
35g butter, cut into cubes
1 tsp vanilla bean paste

1. In a metal saucepan, whisk the caster sugar and cornflour together. Add in a pinch of salt.
2. Measure the milk out into a bowl. Whisk in the eggs yolks and sifted matcha powder, making sure everything is evenly combined.
3. Pour the milk mixture into the saucepan with the dry ingredients, whisking constantly.
4. Add in the butter and heat the saucepan over a medium heat. Keep whisking until the pastry cream begins to boil. The cornstarch will not activate until it reaches a boil. After one minute, add in the vanilla bean paste.
5. Use a mesh sieve the mixture into a separate bowl. Cover with plastic wrap, making sure the plastic touches the top of the pastry cream to prevent a skin from forming. Refrigerate until ready to use.

Assembly:

1. Use a knife or chopstick to create a small hole and tunnel inside the cruffin. It’s best to make the tunnel as vertical as possible.
2. Fill a large bowl with a cup or so of granulated sugar. Roll each cruffin in the sugar. You can also use your hands to sprinkle the sugar over hard to reach areas.
3. Fill a piping bag with the chilled pastry cream. Once all the cruffins have been coated in sugar, pipe the cream into the opening you created until it is filled. Then pipe a small swirl on top. A small sprinkling of cocoa powder can be added to the top of the cruffin.