Add the unsalted butter into a mixing bowl and beat with a hand mixer until butter is creamy and smooth. You can also use a stand mixer with a whisk or paddle attachment and whip.

Add the flour, water and salt into a stand mixer’s bowl and attach the dough hook. Mix on slow speed for 5 minutes or until dough starts to come together. Increase speed and mix for additional 2-3 minutes until dough is mixed.

Transfer the dough onto a floured work surface and shape into a 2 inch width rectangle form.

Using a rolling pin, roll the dough out to 1/2 inch thickness, 10 inches in length.

Cover the dough with plastic wrap rest it for 20 minutes at room temperature.

Remove the plastic from the dough and roll into a 15-inch square, dusting flour as needed.

Using a spatula, spread evenly about a third of the butter onto the bottom half of the dough, leaving a 1-inch space from the side.

Carefully overlap and fold the top half of the dough over the butter. You can use a dough scraper if needed.

Press the edges of the dough to seal and pat the dough with the rolling pin.

Repeat by rolling out the dough to 15 inch square and spread half of the remaining butter onto the bottom half of the dough again leaving about 1 inch space from the edges.

Fold the top portion of the dough onto the buttered portion and press to seal the edges. Pat with rolling pin and rotate the dough so that the seam part is facing you.

For the last application of butter, roll out the dough into a 18 inch square.

Spread the remaining butter over the complete surface of the dough, leaving a 1-inch rim from the bottom edge.

Starting by curling the edge of the dough closest to you and roll into a tight log.

Wrap the rolled dough with plastic wrap and refrigerate for at least 4 hours or until dough is firm. You can also put the dough into a freezer for about 1 hour or until it firms up.

Start by Preheating the oven to 500°F.

In a medium saucepan, add the sugar, water and cinnamon stick and cook over high heat.

Once the sugar mixture comes to a boil, continue to cook for 1 minute then remove pot from heat and set aside.

On a lightly floured surface, trim the ends of the puff dough and make sure they’re even.

Cut the log into thirty ½-inch slices.

Place each slice into an egg tart mold or muffin tin, with the cut side of the spiral facing upwards.

Using your thumb, dipped in water, firmly press down onto the center of the spiral into the bottom of the tart mold and continue pressing to evenly flatten the dough against the bottom and along the sides filling the whole cavity, extending about 1⁄16 inch above the rim of the tart molds or ¾ inch up the sides of the muffin tin.

Repeat this process with the remaining dough.

Refrigerate until firm about 15 minutes.

In the Meantime, place 1 cup plus 1 tablespoon of milk into a medium saucepan and heat the milk over medium heat until it begins to bubble around the side of the saucepan about 5 to 6 minutes.

In a large bowl, add the 1/2 cup of all purpose flour along with the rest of the 5 tablespoons of milk and whisk until mixture is combined.

Continue whisking while slowly pouring in the hot milk

Remove the cinnamon stick from sugar syrup and slowly add the syrup into the milk mixture and mix vigorously in steady stream motion.

Return pot back to stove on low heat and continue whisking constantly for about 10 minutes or until mixture begins to thicken. .

Add in the egg yolks to the thickened mixture and whisk until well combined.

Strain the custard mixture through a fine-mesh sieve.

Fill each pastry shell with the warm custard filling just under the rim about 1 ⅔ tablespoons.

Place pastry filled pastry tarts into oven and bake until the tart shells are crisp and golden brown and the custard tart has caramelized with blackened dots at the surface about 15-20 minutes.

Carefully remove the Portuguese custard tarts from the oven and cool for a few minutes before removing them from the tart molds.

Place onto serving tray, sprinkle with cinnamon and serve warm.