Four more professional chefs from around the country arrive at the MasterChef kitchen ready to put their skills to the test. After two tough challenges, two of them will be sent home while the two strongest contestants will go through to this week's quarter-final.Marcus Wareing sets the first skills test, challenging two chefs to prepare a brunch dish of potato rosti served with egg, bacon and tomatoes. The other two chefs face a test set by Monica Galetti. Timing is everything as they prepare tempura mussels with a smoked garlic aioli. The chefs can't take their eye off the ball or they risk overfrying the delicate muscles.The four chefs then have a chance to redeem themselves of any earlier mishaps as they cook their own two-course signature dishes. They have one hour and 25 minutes to rustle up a main and a dessert that highlight their personal panache.