The Department does not hold data on how many schools teach cooking.
Design & Technology is a compulsory subject for all pupils in Key Stages 1 to 3 attending maintained schools. Academies and free schools do not have to follow the National Curriculum, but may still offer design and technology or teach cookery as part of their own curriculum.
 https://www.gov.uk/government/statistics/revised-gcse-and-equivalent-results-in-england-2015-to-2016 (Subject time series table)
 Based on Key stage 4 qualification and subject data, available at: https://www.compare-school-performance.service.gov.uk/download-data