In a double boiler over medium heat, add the egg yolk and lime juice and whisk constantly until thickened, about 5 minutes. Once thickened, removed the bowl insert from heat and continue whisking.
Add the garlic, salt, and ¼ tsp water.
Slowly drizzle in the grapeseed oil and olive oil while whisking constantly until thicken and emulsified.
Add the cayenne and sriracha and stir well to incorporate.