Spicy Lentil-Walnut Burgers

INGREDIENTS

• 3/4 cup toasted walnuts
• 1/3 cup plain dried breadcrumbs
• 3 cloves garlic, coarsely chopped
• 1 tablespoon minced jalapeno pepper
• 2 teaspoons ground cumin
• 2 teaspoons ground coriander
• 1/4 to 1/2 teaspoon crushed red pepper flakes
• Coarse salt and freshly ground pepper
• 3/4 cup lentils, cooked, drained, and cooled
• 1/4 cup grated onion
• 4 tablespoons olive oil
• 1 large egg
• 4 large pitas
• , for serving Yogurt-Cilantro Sauce
• Sliced avocado, for serving
• Cherry tomatoes, halved, for serving