Cooking So Centre Is Hot

[catsrcool]

I have made this but larger:
https://www.bbc.com/food/recipes/mary_berrys_lasagne_al_16923
and am cooking it in this:
https://www.pyrexuk.com/materials/borosilicate-glass/rectangular-roaster-27x22cm.html
I have made the recipe using the pyrex dish before but I can never seem to get the centre hot.
I have tried slower and lower but I then seem to start burning the edges.
Any suggestions for cooking it so the centre is hot please?
Stick it in the microwave for bit?
Cover it in foil at some stage?
Thanks in advance.

[bookbinder]

My wife suggests cooking at a lower temperature, and increasing the length of the cooking time, but she emphasises that this could involve some guesswork and experimenting.

[sadielady]

Sounds like there is to much food for the container, try using a larger dish

[Old_Geezer]

No real knowledge but maybe use metal skewers to transfer heat to the middle ?

Your link goes to a page showing umpteen Pyrex items. Does glass transfer heat as well as metal or pottery does ? (That said, it seems to heat the outside ok.)

Maybe go for a wider but shallower dish ?