You can use any white fish but the cod goes really well.
Preheat oven to 400° F. Line a baking sheet with parchment paper.
In a plate or baking dish combine pistachios, garlic, salt, and pepper and stir together. In another plate with edges or baking dish whisk egg and Dijon mustard together.
Take each piece of cod and dip into the eggs then roll in the pistachio then set on the prepared baking sheet. Drizzle with a little olive oil.
Bake for 12 minutes.
Add the onion, parsley, roasted red peppers, chicken broth and pepper in your food processor and blend until smooth. Pour into a saucepan and heat to warm through.
To serve add cod to a platter and pour roasted red pepper sauce in a bowl or pour over the fish.