Hi. I tried making the Tiramisini. When I used a hand mixer to blend the mascarpone and honey, the mascarpone broke into little curdled bits instead of a smooth mixture. Adding the marsala didn't help. It tasted okay but the texture was like cottage cheese and not very pleasing. Did I know mix it long enough? (I mixed it for a while after adding Marsala to no avail.) I thought the mascarpone was room temperature but maybe it was still a little too cold? How long can you safely leave it out of the fridge? Thanks for any advice you might have.
Nigella's Tiramisini (from Nigellissima and on the Nigella website) is made with mascarpone that has been lightened with whisked egg whites. Unfortunately it sounds as if the mascarpone curdled because it was whisked too much. Mascarpone has a very high fat content and so will split more easily than double/whipping cream or cream cheese. Once the mascarpone has split it is quite difficult to recover, though if you catch it early (very fine grains) sometimes you can correct it by very gently whisking in (by hand) a little cream.
Also for the Tiramisini recipe the mascarpone does not need to be at room temperature, you can just leave it out of the fridge for a couple of minutes to soften slightly as it softens very quickly. If the mascarpone is warm then it is actually easier to over whisk it. If you try the recipe again then use a very low speed with your mixer and mix the mascarpone and honey until just smooth (this shouldn't take more than a minute), or you could mix them by hand with a wooden spoon.