Fillet the mackerel and remove the pin bones by using a v-bone technique.
Preheat the oven to 180'C.
Cut the beets into wedges and place on a baking tray. Drizzle with olive oil and season with salt and pepper. Cover the tray with foil. Roast in the oven for 30 -45 minutes or until the beetroots are tender.
Cut the bread into thick slices. Drizzle on the olive oil and then rub with a whole garlic clove. Place in the oven for 10 minutes or until golden brown.
Pick and then carefully chop the basil and parsley. Remove the skin from the garlic and puree with your knife and pinch of salt. Zest the lemon.
Dice the anchovies and add to a bowl along with the chopped herbs, capers, mustard, garlic, olive oil and zest of the lemon. Mix well.
Fill the cavity of one fillet of the mackerel with the salsa verde. Place the other fillet on top and tie loosely with a piece of string.
Heat a frying pan until hot and add a splash of olive oil. Pan fry the mackerel for 2 minutes on each side and until golden brown.
Place the mackerel on the toast and serve alongside some of the roasted beets.
«Other oily fish like sardines or herring are also great alternatives to mackerel. "Butterfly" the fish to develop another skill or fillet them as with a mackerel.»