welcome to the forum sandra ,
Do you think that you can let us know the recipe that you are using to make the cake then we might be able to see what the problem is.

Double cream, (I think that I am right in saying) has a higher fat content.

Thnx to mummza and susanneh!!

I made a lemon cake and Jamie's Chocolate Brownies when it happened...
Here's the lemon cake recipe

Ingredients:
115 g butter
115 g caster sugar
4 eggs
180 ground almonds
30 g poppy seeds
zest and juice of 2 lemons
125 g self-raising flour

How to cook:
1. Beat the butter and sugar until light and creamy
2. Add the eggs one by one
3. Fold in the almonds, poppy sedds, lemon zest and juice, and the sifted flour
4. Put into a tin and bake in preheated oven (180C) for 40 mins


That's the recipe....Actually that's a "foreign" recipe...
But I've done all the instructions...

Oh, I have another questions...

Do you know why when you bake cakes, sometimes the cake will be uneven, especially in the middle it will be lower than the other parts...
And also, how to prevent this happening??

Thanks everyone for ur help!! 

Sometimes it helps to turn the cake a bit half way through, when the oven is baking unevenly, but with most cakes that will be the end of it (as it will fall together when the colder air hits before it's done). (My friend had an oven for a while where the cake rose perfectly on the left side, but hardly at all on the right...)

Then to some extend it's something you'll have to live with. Most household ovens don't bake perfectly even.

But if it really is the middle that's flatter, it is possible that it rose while baking, but then came down afterwards. With some cakes that's normal (e.g. most cheese cakes), but with a sponge cake or "normal" cake that might mean that the cake did not take the transition from the hot oven to the cooler room temperature too well. When you take the cake out, try to keep windows shut so that there is no colder drought. Another possibility might be to let it cool in the oven after it's turned off and the door ajar.

Thanks everyone for the help!!

I tried to make the cake yesterday and i suceeded!! 

I just got a recipe from my brother, this is a lemon cheese cake...
If u try it and it turns out great, let me know, ok?!

Here it is...
Lemon Cheesecake:

3/4 cup graham cracker crumbs
2 tablespoons granulated sugar
1 tablespoon ground cinnamon
1 tablespoon butter or margarine, softened
40 ounces cream cheese, softened
1 2/3 cups granulated sugar
5 eggs
1/8 teaspoon salt
1 1/2 teaspoons vanilla extract
1/4 cup lemon juice

Combine the first 3 ingredients; stir well, then set aside.
Grease the bottom and sides of a 10−inch
springform pan with butter. Add crumb mixture; tilt pan to coat sides and bottom. Chill.
Beat cream cheese at medium speed with an electric mixer until light and fluffy; gradually add the 1
2/3 cups sugar, beating well at high speed. Add sugar, beating well at high speed. Add eggs, one at a
time, beating well after each addition. Stir in salt, vanilla extract and lemon juice.
Pour mixture into
the prepared crust. Bake at 300 degrees F for 1 hours and 20 minutes. The center may be soft, but will
set when chilled.
Cool on a wire rack; cover and chill for 8 hours.