Place the macadamias and water in the jug of a high-speed blender and blend for 2-3 minutes. Place the mixture in a nut bag and squeeze out the excess moisture. Note: you can keep this liquid and use it in a recipe requiring macadamia milk.
Place the macadamia mixture in a food processor with the remaining feta ingredients and blend thoroughly until the mixture is combined. Carefully add more salt or lemon juice, a little at a time to taste, being careful not to add too much.
Line a colander or sieve with cheesecloth and place the mixture in it. Pat the mixture into a small slab that is 2-3cm thick and fold the muslin over to enclose. Place in the fridge for at least 12 hours to set. Remove from the muslin and cut into 2 x 3cm rectangular pieces.
Gently place the pieces in a jar, alternating with the peppercorns, thyme and bay leaves. Pour over the oil to cover, place a lid on the jar and keep refrigerated until ready to eat.