How to avoid vegetables sticking on heat-resistant glass dish? Sometimes I cook vegetables + fruits in a heat-resistant glass dish (yena/jena/pyrex, -40-300 Celsius degrees). I cut them into small pieces (carrots, potatoes, parsnip, mushrooms, onion, quince, apples, tomatoes, pepper, cauliflower, broccoli), I add some spices (salt, pepper, paprika) and some butter, and I put the dish (with the lid) into the gas oven for about 2 hours.

Everything is good, excepting the fact that some of the vegetables/fruits stick to the dish walls (not on the bottom side) and get burnt. Greasing the dish walls with butter didn't solve the problem.

Does anyone have a solution?
Butter has a fairly low smoke point, and may be burning in the oven. You could try using one of the "yellow oils" like canola (rapeseed), peanut, soybean or corn oil.

Aside from that, it's not completely unexpected for cooking vegetables to stick to the edge of a dish. It may just be normal behaviour. My apple pies will always stick slightly to the edges of the pie dish.