I make my own sponge cake I added sugar to taste and a squeeze of lemon. I placed it in the a bowl and poured the sponge cake batter on top and baked in the oven at 180 for 25 mins. I did alter the batter recipe to 3 whole eggs I just folded the white and wow a beautiful dessert. This was a couple of times I baking a cake i am glad the result tasted good. was a bit nervous It should be around 25 minutes to bake the thickness of the cake for an 11 inch tin is the same as that of the 8 inch tin because you are adjusting the amount of batter according with different tin sizes. However, the baking time will also depend on your oven heat. Not all ovens bake the same way, so it really should be based on your experience in using your oven. But use the 45 - 50 minutes as a general guide and test your cake with a toothpick to check if it is done. My kid and my friend's kids like my cake every 10 minutes they come back to the kitchen and eat it, lol. they like it. I bake also a chocolate cake which is my favorite cake. Might be, I have to bake again enjoy watching yum,yum.