Melt the butter in a cast iron skillet.
Sprinkle the cod fillets with salt and pepper.
Sear cod on each side, cooking until just cooked through (do not over cook, cod should still be slightly translucent in the center).
Remove the cod from the pan. Add the tomatoes, cooking over high heat until blistered and soft.
Add the garlic, stir until fragrant, about 30 seconds.
Stir in the lemon juice and beer. Cook over medium high heat, breaking up and smashing the tomatoes. Cook until reduced and thickened.
Stir in the herbs and additional salt and pepper to taste.
Plate the cod with the tomato sauce.