I would have a special “gay recipe” just for those special occasions,not written down of course. The cake would have just a little more salt and a little less sugar. Also, an occasional hair in the icing here and there. Can’t help it if people don’t like the way it tastes...darn, did We put too much salt in it...so sorry, I’ll be more careful next time. If you got a bad cake from a baker, you would complain...in this case you would also give a satisfaction guarantee. And you would replace the cake for free later, after the queer nuptial was over, in which case it would now be a replacement cake, not a wedding cake. Baking a second cake would be cheaper than paying a fine, and who could prove it wasn’t just a mistake?
Might be satisfying to do it that way, but it is not the Christian way. Christians are to do their work unto the Lord, to the best of their ability. The best alternative I can see other than refuse to bake it at all is to have prominent signage stating something like “Notice: All proceeds received from the sale of cakes that celebrate homosexual unions will be donated to (insert homosexual reparative therapy ministry of choice). Thank you in advance for your support of this valuable ministry!” The homosexual clients would likewise be given a loud, enthusiastic “thank you” for their donation to the ministry at the time of purchase.