Clean the leeks and cut into thin rings.

Heat the oil in a skillet. Add the leeks and cook, stirring frequently until the leeks have softened.

Season with sugar, salt and freshly ground pepper to taste.

Remove from heat and set aside to cool.

In a separate bowl, whisk together the sour cream, eggs and lemon juice.

Add the 1/2 cup parsley and tablespoon of thyme, mix and season with salt and freshly ground pepper to taste.

Fold the cooked leeks into the cream mixture.

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

Roll the puff pastry sheet out onto a lightly floured surface. Transfer to the baking sheet.

Spread the leek cream out onto the puff pastry.

Evenly distribute the cut bratwurst over the top.

Place in oven and bake for 30 minutes.

Remove from oven, let cool for 10 minutes.

Garnish with fresh parsley and oregano. Cut and serve.