Vegetarian tacos with celery, sweet potato, and pineapple salsa

Ingredients:

• 2 medium sizes sweet potato tuber, cut into pieces approximately 2.5 cm in size.
• 5 cloves of garlic (unpeeled)
• 1 large red onion, coarsely sliced
• 1 medium celery root, peeled and cut into pieces about 2.5 cm in size.
• 1/4 cup vegetable oil
• Salt and freshly ground black pepper
• 1/4 pineapple, cored
• 1 serrano chili pepper
• 1/3 cup finely chopped parsley
• 2 tablespoons lime juice
• 3/4 cup refried beans
• 12 corn tortillas, 15 cm in diameter.

Preparation:

1. Place oven racks on the top and bottom of the oven; preheat to 450°F (230°C). Spread the garlic and all but two slices of red onion (these will be used for making the salsa) on a rimmed baking sheet. Place the sweet potatoes and celery root on a separate rimmed baking sheet.
   
   Spray both baking sheets with 2 tablespoons of sunflower oil and season with 1/4 teaspoon of salt and a little freshly ground black pepper. Bake, turning the vegetables and rotating the baking sheet occasionally, for 25-30 minutes, until the vegetables are caramelized. Let the dish cool.
2. Meanwhile, finely chop the remaining red onion, pineapple, and serrano pepper (remove the seeds to reduce some of the heat); combine in a medium bowl. Add half the parsley and lime juice, and season with salt and pepper to taste.
3. In a separate small bowl, squeeze the roasted garlic cloves out of their skins and crush them. Add the beans and mix thoroughly. Cover the bowl with plastic wrap and microwave for about 2 minutes.
   
   Heat the tortillas according to package directions. Spread the bean mixture on each tortilla and top with the roasted vegetables, pineapple salsa, and remaining parsley.