Cut parchment paper into 4 large squares (approximately 12” x 12”).
On a flat surface, place a cod fillet on one square, positioning it toward the bottom center of the paper. Sprinkle the cod with salt and pepper. Top the fillet with sliced tomatoes and a drizzle of pesto.
Fold the parchment paper in half and seal the bottom edge by tightly folding where the two halves come together. Repeat on each side.
Set the sealed pack on lined baking sheet and repeat process with remaining 3 cod fillets. When finished, place baking sheet in pre-heated oven on center rack and bake for 8-10 minutes. Remove from oven and serve immediately.