There aren't many places you can go with a toddler just to cook, apart from in your own home. Most Stay and Plays and playgroups do some cooking from time to time.
Crafty Cooks has a centre in Northampton for those who live that way info@craftycooks.co.uk http://www.craftycooks.co.uk 01628 476670
Smart Raspberry is in MK. Different classes do different ages https://www.smartraspberry.com asmaawan@smartraspberry.com 07999 118098
Kids Cooking Activities online, some good ideas and videos
https://www.kids-cooking-activities.com/apple-recipes.html