I made some of these to have with salads and I had it with with some salad in a home made gf bread roll.
The burger I made with sliced chestnut mushrooms, onion, yellow sweet pepper, which I gently cooked in olive oil with grated coconut butter then and then added grated sweet potato chia seeds sesame seeds, pumpkin seeds with cumin, coriander, turmeric and ginger. Then I added some water with plain gf flour and mixed thoroughly.
Chia seeds are really good at helping to thicken and bind foods as they absorb 10x their weight of water, so are also great for thickening fruit. And they're very healthy...
Unfortunately you can't see the burger very well in the photo because of the salad but I was trying to get a side shot like they do in the adverts...LOL...😊