Hi,
The liability of cakes is generally at the zero rate of VAT. You can see the guidance at section 3.6 here:
Food products (VAT Notice 701/14)
If the cakes are being consumed on the premises then this will be a 20% supply of catering. You can see guidance here:
Catering and takeaway food
If your taxable supplies are above £90000, then you would need to register for VAT. However, you can choose to apply for an exemption if most of your sales are zero rated. Please see the guidance at section 3.11 here:
Working out whether you need to register
Thank you.