Cut the ends off brussels sprouts and cut them in half. Slice red onion into thin half moons. Heat a large cast iron or non-stick skillet over medium-high heat. Add 1 tsp coconut oil. Saute onion 2-3 minutes or until onion begins to soften and caramelize. Add brussels sprouts, salt, and pepper. Cook until sprouts begin to brown and stick a little to the pan about 4-5 minutes. While sprouts are cooking, combine veganaise, honey or agave, and sriracha together in a bowl and set aside. Add 1/3 cup water to pan to steam sprouts. Cook for another minute or until water absorbs. When brussels sprouts have started to soften (not mushy...don't overcook or they will taste bitter!) add sauce, stir and turn off heat, but leave on the burner for another minute. Serve warm and enjoy!