1: Preheat oven to 180°C (360°F). Prepare 400 g mushrooms and slice.
2: Pour them into a salad bowl, add 4 tablespoons olive oil, salt and pepper, and mix thoroughly. Note: the best way to mix them well is to place a plate on top of the bowl and shake, holding them firmly.
4: Place in the oven for around 30 minutes at 180°C (360°F). Your mushrooms should be reduced in size and nicely browned, so don't forget to check their seasoning. Set aside.
7: Meanwhile, in a large frying pan over medium heat, pour in 30 g butter and when frothy, add shallot, 1 garlic clove, salt and pepper. Cook for 1 minute.
11: Finally, add the tagliatelle as soon as it's cooked, mix well and serve without delay.
Remarks
For the mushrooms, feel free to mix several types, depending on what's available when you make the recipe. You can also add the spices of your choice to the mushrooms in step 2: paprika, chili, curry... This recipe is sometimes found with smoked chicken instead of spinach.