Using a paper towel, pat the mahi mahi fillets dry on both sides before generously seasoning them with salt and pepper.
Heat the olive oil and butter/ghee in a large skillet on medium high heat. Once hot add in the mahi mahi fillets and leave them to cook untouched for 3 minutes until they are golden brown in colour and then flip them over and cook for an additional 3 minutes on the other side. Set the cooked mahi mahi aside on a plate.
Add the tomatoes to the pan and leave them to cook for 4 minutes until they begin to blister and then add in the diced shallots and garlic and cook for 1 minute until fragrant.
Next add the chicken stock, white wine vinegar and lemon juice to the pan, bring to a simmer and leave to cook for 4 minutes. Stir in the lemon zest and chopped basil. Return the mahi mahi fillets to the pan. Spoon the sauce overtop each fillet before serving.
