Hong Kong Puff Pastry Egg Tarts, Sweetened with Monk Fruit

Method

1. For the butter dough, cut 45g cold unsalted butter into small cubes and work it into 50g all purpose flour with your fingertips until it forms a soft but still cold block. Add 2 teaspoons very cold water if it is too dry, then wrap it and chill it for 15 to 20 minutes.
2. For the water dough, put 100g all purpose flour, 50g cold unsweetened oat milk, 18g kOBE Monk Fruit Blend, 20g cooking oil and 1g salt in a bowl and knead gently for 2 to 3 minutes until smooth and pliable.
3. Roll the water dough into a rectangle 0.3 to 0.4cm thick, set the flattened butter dough in the middle and fold the edges over to seal it in.
4. Roll it long, fold it in thirds like a letter, turn it 90 degrees and repeat, four times in all. If the dough softens, chill it for 20 to 30 minutes before carrying on.
5. Roll the block to 0.3 to 0.4cm thick, roll it up tightly along the long side and cut it into 11 to 12 rounds of 25 to 27g each.
6. Flatten each round, roll it into a thin circle 0.3cm thick and press it into a cupcake mold, leaving the rim slightly above the edge. Chill for at least 30 minutes.
7. For the filling, heat 150g unsweetened oat milk with 100g whipping cream to about 50 to 60 degrees C without letting it boil.
8. Whisk 3 egg yolks with 45g kOBE Monk Fruit Blend and 2g salt, sift in 25g cornstarch and whisk it smooth, then pour in the warm milk and cream in a slow stream while stirring.
9. Return everything to the pot and cook over medium heat, stirring constantly, until the mixture thickens slightly. Take it off the heat, add 3/4 teaspoon liquid vanilla and cover it to keep it warm.
10. Heat the oven to 175 degrees C for 15 minutes and blind bake the shells for 8 to 10 minutes.
11. Strain the custard and divide it among the baked shells, filling them only about 2/3 to 3/4 of the way up.
12. Bake at 175 degrees C for 30 to 35 minutes, one rack below the middle, until the shells are deep golden and the custard still wobbles slightly in the center.

Tips

• Butter and dough kept very cold through every roll is what keeps the layers separate, since melted butter fuses them and costs the shell its crunch.
• Cooking the custard partway on the stove is not optional, because skipping it lets the cornstarch settle into a rubbery layer at the base.
• The tarts taste better warm or cooled than piping hot.
• Custard strained before it is poured gives a smooth surface.
• Four rolls and folds are enough, because more makes the butter layers too thin and the shell loses its lift.