The cost of making a classic Pizza Margherita rose more than twice as fast as overall inflation in Italy last month, driven by the surging price of olive oil and mozzarella cheese.

The total amount spent on ingredients and energy to cook the quintessential Naples dish rose 18.4% in May from a year earlier, according to Bloomberg calculations based on Istat and Economy Ministry data.

The monthly gauge continues to far outstrip the overall inflation rate, which stood at 8% last month. Still, the pace of price increases eased from April and compares with a November peak of more than 30%.

The cost of buying a prepared pizza rose only 7.7% year-on-year, increasing the appeal of going out to eat.

Bloomberg’s Pizza index crunches data on flour, tomatoes, mozzarella, olive oil and the electricity consumption needed to power an oven. The biggest month-on-month increase was for tomatoes, which were 7.5% more expensive than in April. Energy was the only item that fell, down 1.4%.

Here is a breakdown of the change in the price of ingredients in May:

• Flour rose 9.4% Y/y and 0.3% M/m
• Mozzarella rose 22.1% Y/y and 0.3% M/m
• Tomatoes rose 18.2% Y/y and 7.5% M/m
• Olive oil rose 24.6% Y/y and 1.0% M/m
• Electricity rose 13.5% Y/y but fell 1.4% M/m

The cost of pasta also rose again in May, according to Istat data. Consumer advocate group Assoutenti has called for a national pasta boycott from June 22 after the government in Rome decided not to act to counter higher prices at a meeting last month.