I haven’t checked to be sure, but I think the forum posts that talk about putting these recipes into rectangular pans without making adjustments are talking about a smaller pan than yours, 9x13.

There is a written example on p. 489 of how to follow the process of using the Rose Factor charts, that may be helpful.

Here’s what I would do:

- you need to find two things, first the number of base recipes that will fill your pan, and second the correct “level” for figuring out baking powder quantities.

- to find the correct “level”, look at the chart on p. 490. Your exact pan size isn’t listed there, but since it is between the two sheet pan sizes in “Level 6”, I’d say that would be a great place to start. That is, if a similarly shaped pan smaller than yours and another larger than yours are both level 6, then level 6 will likely work for your pan as well.

-To find the right amount of batter (i.e., number of base recipes) to use, first find a pan with the same capacity as yours. From the chart on p.455, you can see that a 15x2 round pan has a capacity of 24 cups, a little more than yours, and the 14x2 round has 21 cups, a little less than yours. For now, let’s look at the 15x2 pan.

-Back to the chart on p.490, you can see that *two layers* in a 15x2 round pan have a Rose Factor of 12, you’re making one layer (I think), so you would need half as much, or a Rose Factor of 6. Your pan is a little smaller than the 24 cup pan, so you can either use 5.7 for your Rose Factor or use 6 and bake a few cupcakes.

**To sum up so far, to bake one layer in your 11x15x2 pan, you’ll use a baking powder level 6 and a Rose Factor of 5.7 or 6. **

-Next, to get your quantity of ingredients, multiply the base formula on p.491 by your Rose Factor of 5.7 or 6. So for a RF6 you’ll need 9 egg whites, two cups of milk, etc. As for baking time, I would estimate something between the two rectangular pans, so something like 37-47 minutes.

-Finally, to get the right level of baking powder, look at the second chart on p. 492 and you’ll see that level 6 cakes need 1.25 tsp per base, so multiply 1.25 tsp by 5.7 or 6 to get the right amount of baking powder.

**So, all in, you would multiply the base recipe on p.491 by six, use 7.5 tsp of baking powder, and bake for 37-47 minutes. Be sure to use cake strips. And remember to bake a few cupcakes in order to make sure your pan doesn’t overflow. **

Note that in the chart on p. 490, the Level six cakes are only for one layer, while the rest of the chart is for two, and that the baking times for the two level six cakes are reversed. There’s an errata section on this website, that’s one of the few errors in the book.