Trigona Panoramatos (Phyllo Custard Triangles)

Instructions

1. Make the custard first so it can chill: in a saucepan whisk the 120 g granulated sugar, cornstarch and all-purpose flour, then whisk in a little of the whole milk until smooth, followed by the egg yolks and the rest of the milk. Cook over medium heat, whisking constantly, until thick, bubbling for 1 minute and at least 160°F (71°C), 8 to 10 minutes.
2. Off the heat, whisk in the 40 g unsalted butter and the vanilla extract. Press plastic wrap onto the surface, cool, about 1 hour, then refrigerate until cold and firm, at least 3 hours.
3. Make the syrup: boil the 400 g granulated sugar, water, light corn syrup and split vanilla bean for 8 minutes, stirring until the sugar dissolves. Stir in the lemon juice, remove the vanilla bean and let cool to room temperature, about 1 hour.
4. Heat the oven to 350°F (175°C). Keep the phyllo dough covered with a damp towel. Cut each sheet lengthwise into 3 strips about 4 1/2 inches (11 cm) wide.
5. Brush one strip with the 150 g melted unsalted butter, lay a second strip on top and brush again. Fold one bottom corner up to the opposite edge to make a triangle, then keep folding the triangle up the strip, flag-style, to the end. Brush with butter and set on a lined sheet. Repeat to make 18 triangles.
6. Bake until deep golden and crisp all through, 25 to 30 minutes.
7. While the triangles are hot, dip them 2 or 3 at a time into the cool syrup for 30 to 60 seconds, then lift out and drain on a rack, open edge down, until cool, about 30 minutes.
8. With small scissors, snip open the top edge of each triangle and pull out a little of the inner pastry to make a pocket. Beat the cold custard briefly until smooth, spoon it into a piping bag and fill each triangle generously.
9. Dust lightly with the powdered sugar and serve right away, or refrigerate up to 4 hours before serving.