Heat the oil in a large saucepan
over medium-high heat. Add the fennel
, onions and garlic and cook, stirring frequently to prevent sticking, for about 10 minutes. Then add the tomatoes, peppers and thyme. Continue to cook and stir for 8 minutes. Add the white wine
and cook until it has reduced by half. Then add the fish stock
. Increase the heat and bring to a boil. Add the fish and decrease the heat to a simmer
. Cook for 5 minutes. Add the basil and Espelette, then turn off the heat and let cool slightly. Place the sauce into a blender and blend until smooth. Season with salt and pepper.
Cook's Note: When blending hot liquids, remove liquid from the heat and allow to cool for at least 5 minutes. Transfer liquid to a blender or food processor
and fill it no more than halfway. If using a blender
, release one corner of the lid. This prevents the vacuum effect that creates heat explosions. Place a towel over the top of the machine, pulse
a few times then process on high speed until smooth.