Preheat oven to 350F/175C. I’ve found an 8 inch Pyrex pie dish works best. Grease the sides with the butter and then into the microwave to melt the rest.
Combine all ingredients except the peaches/berries. Pour 1/2 of the fruit into the pie dish and pour the mixture into the baking dish and then put the rest of the peaches/berries on top.
Dust with the tablespoon of sugar and bake for 350F/175C for 35-45 minutes. Check after 35 minutes. If it jiggles when you shake it, it’s not done. Normally I need 45 minutes for it to set completely. Finish with broiler if needed.