If baking the sliders, preheat oven to 400°F/200°C (not necessary for grilling).

Slice tempeh into strips and place into a medium pot on medium-high heat. Cover with vegetable broth and let come to a boil. Once broth is boiling, reduce heat and let simmer for 10 minutes. Drain vegetable broth and set tempeh aside.

Heat olive oil in a medium-sized skillet over medium heat. Add chopped red onion, mushrooms, and minced garlic. Cook until soft, stirring frequently.

Meanwhile, make a flax egg by combining 1 tablespoon of ground flaxseed with 2.5 tablespoons water. Let sit for 5 minutes to thicken.

Then, add all ingredients to a food processor. Pulse until combined. At this point, the mixture will be very thick and you may need to transfer to a bowl and combine with a spoon. 

Using both hands, take a small handful of the mixture and roll into a ball. Then, press the ball between your palms to make a small slider patty, depending on the size of the buns you're using. Ours were about 4 inches.

If Baking: place on baking sheet and bake in preheated oven for 20 minutes, flipping halfway through.

To Grill: heat your grill or stovetop grill pan on medium heat. Grill sliders for 4-5 minutes on each side. 

Serving Suggestion: Toast slider buns and spread basil pesto on bottom bun followed by a large basil leaf. Spread homemade tomato sauce on the tempeh slider patty. Then, top with caramelized onions and mushrooms. We also topped with jalapeños because we like it spicy.