Savory filling: caramelized onion and blue cheese

Ingredients

• Tart dough: I used this one with rye sourdough: sourdough tart dough
• 2 onions
• 70gr blue cheese or gorgonzola
• 30ml creme fraiche
• 1 egg
• salt
• max 10 tablespoons beer (optional – you can use water also)

Steps

• Cut the onion in thin slices and cook it in low/medium fire for approximately 30 minutes till it is transparent and slightly brown
• While being cooked it will need more liquid. You can add water or beer or wine but always in small quantities like 1-2 tablespoons
• When cooked, let it cool down. Either place it in a bowl to cool down quicker or wait for it to cool down in the pan
• Beat the eggs and add the creme fraiche and the salt
• Add in the onion the blue cheese and mix
• Add also the eggs mixture
• Make holes in whatever tart dough you are using
• If you use small individual tarts you need around 28 minutes in preheated oven in 200 degrees Celsius. If you are going to make a bigger one and a higher tart, you will need to bake it longer

Hint! You can also put this filling in muffins like in the foto or make a closed pie, so with one more layer of tart dough on top