Heat a large fry pan with a medium heat and add in the olive oil

After a couple of minutes, add in the sliced onions, mix together, and then mix every 1 to 2 minutes so they evenly sauté

In the meantime, add the cod fillets over some paper towels and pat completely dry, then season with salt & pepper on both sides; do the same thing with the shrimp, but just season on one side

After sautéing the onions for about 10 minutes and they're translucent, add in the chopped garlic and mix continuously, after 1 minute, add in the flour and mix continuously for 1 minute, then add in the white wine, dried thyme, and crushed red pepper, and continue to mix together

Once the alcohol has been cooked off in the wine, about 3 minutes, add in the fish broth, gently mix continuously, and go for 4 to 5 minutes or until you get a slightly creamy sauce, then season with salt & pepper, and mix together

Add the cod fillets into the pan, all in a single layer, and then gently flip each one, then add the shrimp, once again all in a single layer, then place a lid on the pan, and lower to a low medium heat, simmer for 5 to 6 minutes, or until the cod and shrimp are just cooked through

In the meantime, make the garlic sauce, add the chopped garlic, chopped parsley, and a pinch of salt into a mortar, and using a pestle, pound down on the ingredients until you get a paste-like texture, then add in the olive oil and lemon juice, and mix together

Once the cod and shrimp are just cooked through, remove the pan from heat, top off the cod fillets with the garlic sauce, and garnish with lemon wedges, serve at once, enjoy!