In a large bowl, add the flour, sugar, baking powder, and yeast. Pour in the warm water and stir with chopsticks until the mixture forms evenly hydrated shaggy crumbs with no dry flour remaining.

Add the corn oil or butter and knead by hand until the dough becomes smooth, elastic, and no longer sticks to your hands or the bowl. This takes about 10 minutes.

Cover the dough with plastic wrap or a damp cloth and let it rest for 10 minutes to relax the gluten.

In a separate bowl, combine the flour and corn oil.

Mix thoroughly until the flour fully absorbs the oil, then knead lightly until a smooth, non-sticky oil dough forms. This dough does not need to rest and can be used immediately.

Place the rested water dough on a lightly floured surface and press it into a round disc about 20 cm in diameter.

Place the oil paste in the center of the water dough.

Wrap the dough around it completely and pinch the seams tightly so the oil paste is fully sealed inside.

Roll the dough into a rectangular sheet about 0.3 cm thick, keeping the thickness as even as possible.

Fold both short ends toward the center and press gently to seal.

Roll the dough out again into a rectangle and repeat the fold one more time. This completes the lamination. Avoid over-folding, as too many layers can cause them to stick together.

Roll the laminated dough into a large, even sheet. Sprinkle sweet red beans evenly over two-thirds of the surface, keeping the edges clear.

Fold the unfilled third over the red bean layer and press gently.

Fold the remaining section over to create a three-layer stack.

Roll lightly until the dough is about 1 cm thick.

Cut into desired shapes, such as squares or rounds.

Preheat the oven to 160°C (320°F), top and bottom heat, for 10 minutes.

Arrange the pastries on a baking tray. Brush the surface evenly with egg yolk and sprinkle with white sesame seeds.

Place them in a warm area and let proof for 20 minutes, until about 1.5 times their original size.

Bake on the middle rack at 160°C for 25 minutes, until golden, flaky, and slightly puffed.

Remove from the oven and let cool for 5 minutes before serving to allow the crust to crisp further.