Smoky cumin and peppery basil provide perfect balance to the sweet pineapple and tangy relish that top these incredible veggie burgers. Choose pineapples that are slightly soft to the touch, with a full, strong color and no signs of greening. Leaves should be crisp and green, with no signs of browning or yellowing.
In a medium skillet heat cumin seeds over medium heat until they are fragrant and starting to brown, about 3 to 4 minutes. Transfer to a cutting board. Crush seeds using a mortar and pestle or with a rolling pin.
Brush burger patties with olive oil; coat with crushed cumin seeds. Blot excess moisture from pineapple slices and lightly coat with olive oil.
Grill pineapple slices on the rack of an uncovered grill directly over medium-high heat for 3 to 4 minutes per side or until heated through. Transfer to a cutting board. Add meatless patties to grill rack; cook for 4 minutes per side or until heated through, adding pita bread the last 3 to 4 minutes of grilling. Cover and keep warm.
Chop pineapple and place in a bowl; stir in relish.
Serve veggie burgers on pita bread with pineapple mixture. If desired, top with fresh basil and chopped peanuts.