Place the flour, salt, unsalted butter and two eggs in a mixer and use the dough hook attachment to mix into a smooth, shiny, dough.

Wrap the dough in plastic cling film and place in the refrigerator for 30 minutes.

Cut the red onion into small fine pieces.

Melt the 2 tablespoons of unsalted butter in a small frying pan over medium heat.

Sautée the onions until they are soft.

Add the baby spinach and sautée briefly.

Lower the heat, cover and cook about 10 minutes.

Add the peas and cook everything

until the liquid evaporates. Mix and season with salt and freshly ground pepper to taste.

Let the mixture cool before using.

Remove the strudel dough from the refrigerator. Let the dough sit 10 minutes on the counter and then knead a few turns on a lightly floured surface once more to make it pliable.

Roll the dough out into a large rectangle.

Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.

Cut out 16 triangles about 5 inches each in width.

Brush the dough triangles with egg white.

Place a small amount of the vegetable filling on the center of the dough triangle.

Sprinkle a bit of grated Emmental on top. Fold the triangle over, then pinch the dough on all sides with your fingers to seal.

Lay the filled dough triangles on the prepared baking sheet. Brush the filled triangles with egg yolk.

Bake for 25 minutes until golden brown on top.

Remove from oven and transfer to a wire rack to cool.

Let the mini strudel stand 10 minutes before transferring to a baking sheet. serve warm.