How to... bake and ice a Number Cake

Number cakes are a fun way to celebrate and always look great as a centrepiece. Here’s how to bake and ice a number cake by Britt Box from She Who Bakes.

Brought to you by Britt Box from She Who Bakes

Number cakes are a fun way to celebrate. They are adaptable and always look great as a centrepiece. Here’s how to bake and ice a number cake – Britt Box from She Who Bakes (

A lot of number tins, including the ones I like to use, are bottomless and essentially just a frame in the shape of a number. I hired these from my local cake shop, but they are available to purchase online. You can also buy silicone number tins, which do have a bottom to them, but as the metal ones tend to be more common, that’s what I’m going to take you through.


As the tin has no bottom we will need to create one, then we can line the tin as normal. YOU WILL NEED

  • a number tin
  • 1 x baking tray per number
  • greaseproof/baking paper
  • foil
  • scissors
  • pencil
  • Cake Release
  • silicone pastry brush
  1. Because I flip my cakes over once they are baked and use the top as the bottom to make it nice and level, I need to make sure I flip my tin over so it bakes the wrong (right) way around, otherwise I will have a back to front 7.
  2. Draw around the inside of your number(s) onto the greaseproof paper, then cut them out. Put these to one side for now.
  3. To create the ‘bottom’ for the tin, place the number onto a sheet of foil, folding up the sides tightly around the number.
  4. To properly line the tin, paint the inside with Cake Release. Roll out greaseproof paper to the circumference of your number tin, then cut a strip that’s about 2.5cm (1in) deeper than the tin itself. Roll this strip back up. Gently unravel a strip of greaseproof paper along the inside, pressing it firmly against the sides to stick down. Do the same for the middle of the number, wrapping this in a strip of greaseproof paper too.
  5. Paint the bottom of the foil ‘tin’ you have made, then stick down the greaseproof number you cut out earlier. Repeat this for any other numbers you are doing. *Note* When lining a zero, make sure to cut the inside hole a little bigger to fit over the frame.


  1. You can use any mix you like for a number cake, but I like to use a Madeira cake as it’s a nice strong sponge. You just need to make sure it’s enough mix for a 20cm (8in) round cake. That tends to be enough to fit the tin.
  2. Once the cake is baked, check for any ‘leakage’. I got some in the corner of the 7 and the hole of the 0, but a little bit is absolutely fine, it just means we get a little snack!
  3. Leave the number cakes to cool in the tin for a few hours with a tea towel over the top, just to make sure nothing can get into it.
  4. Once the cakes are cool, carefully turn them upside down, then turn out of the tin and wrap well in clingfilm. Leave overnight. They can be very delicate, so giving them time to firm up will really help when splitting and filling them.


  1. Firstly, level the cake by cutting off any excess rise using a cake leveller or serrated knife, then very gently flip the cake over. I will be filling my cake with a dense vanilla buttercream for stability. I used 500g (1lb 1oz) unsalted butter, 1kg (2lb 2oz) icing sugar and 2 tsp good quality vanilla; this was enough for both numbers. If you’re only making one number you can halve this recipe.
  2. Using a cake leveller, cut into your cake. I always split mine twice so I can even out the filling, and it looks pretty when you cut into it too! I make the first cut one-third of the way up the cake, and another halfway between the first cut and the top of the cake.
  3. Use another thin cake board to slip between the layers and lift up the rest of the cake, otherwise, you may risk breaking the sponge as it will be thin around the edge. Spread over your buttercream filling and jam, if you’re using it, then using the thin cake board, slide the top section of the cake back onto the filled section. Repeat for the second layer. Pop this into the fridge to firm up for 15 minutes while you do the same for the second number.
  4. Once your cake has chilled you can crumb- coat it. This is when you spread a layer of buttercream on the outside of the cake to keep the crumbs in, help keep the cake fresh and to act as an adhesive for the sugarpaste/icing. Once you have done one layer, pop it back in the fridge briefly for about 5 minutes, then do a second layer. This ensures a nice smooth finish under the suparpaste/icing.
  5. I am covering my number cakes in a layer of sugarpaste. For this, I am using 1kg (2lb 2oz) icing per number. Roll out the icing, onto a surface dusted with cornflour, between spacers, or to 5mm (1⁄4in) thick. Using a rolling pin, gently lift up the icing and place it gently over the cake. Start to smooth it with your hands in a ‘scooping up’ movement so as not to tear the edges, then carefully cut away the excess icing.
  6. If your number has a hole in the middle, make a small cut in the middle of the icing dip using a sharp knife, then smooth down the icing into the hole as far as it will go. Don’t try and make it touch the bottom as there won’t be enough and you risk ripping and tearing the inner edge. Instead, cut a strip of sugarpaste and place it in the middle of the hole. Using your hands, gently push this onto the cake, smoothing down as you go. There will be a small trace of a line, but nothing noticeable. Complete this with a smoother and smooth the rest of the cake too.
  7. For the '7' and numbers with sharp edges, corners are the trickiest bit. There will likely be gaps when you’re covering the cake. To cover these, cut a shape loosely like the gap and push this into place. Smooth it down with your fingers, at first in circular motions to stick down, then use a smoother to finish.
  8. If you’re going to 'crimp' the outline of your cake as I have done, do this now. Leave the cakes to set overnight before trying to move or decorate them. It’s much easier to work with harder, set icing than soft icing as you risk damaging it. I recommend icing the board now too; I’ve gone for a marbled purple style, but the choice is yours! I’ve used a 50x35cm (20x14in) cake board to fit both numbers. A single number would only need an 45x35cm (18x14in) board.
  9. I recommend finishing the cake the following day. The best way to stick a cake onto an iced board is by using royal icing, the cement of the cake decorating world. Having measured roughly where I wanted to place my cake onto the board, I painted an '0' with royal icing. I then used 2 large palette knives to carefully lift the number into place – be careful when pulling the palette knives out. Pull them out straight and firmly, not at angles otherwise you risk damaging your sugarpaste/icing. Lastly, leave the cake to set on the board for a few hours before decorating as desired!

Watch our video for an clearer idea of each step! [video width="1280" height="720" mp4="" loop="true"][/video]  

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