Creating your Juicy Portobello Mushroom Burgers with Pesto is straightforward. Follow these simple steps:

1. Preheat the Grill or Grill Pan: Preheat to medium-high heat.
2. Prepare the Pesto: In a food processor, combine basil, pine nuts, Parmesan cheese, garlic, and a pinch of salt. Blend until finely chopped. Gradually add olive oil while blending until smooth. Adjust seasoning to taste.
3. Clean the Mushrooms: Wipe Portobello mushrooms with a damp cloth to remove dirt. Remove the stems and gills gently using a spoon for a cleaner look.
4. Marinate the Mushrooms: Brush both sides of the mushrooms with olive oil. Sprinkle with salt and pepper. Let them marinate for about 5 minutes.
5. Grill the Mushrooms: Place the mushrooms on the preheated grill. Cook for 5-7 minutes on each side or until tender and charred.
6. Toast the Buns: While the mushrooms are grilling, place the burger buns cut side down on the grill. Toast until golden brown.
7. Assemble the Burgers: Spread a generous layer of pesto on the bottom half of each burger bun. Top with the grilled Portobello mushroom, arugula (or spinach), and additional toppings like tomato or avocado if desired.
8. Complete the Burger: Place the top half of the bun on the stacked veggies and mushrooms.
9. Serve: Enjoy your hearty, Juicy Portobello Mushroom Burgers with Pesto warm!

This step-by-step guide will help you effortlessly prepare an incredible meal that tastes as good as it looks!