In a medium saucepan, add the sugar and cook over medium heat, stirring constantly with a heat resistant spatula or wooden spoon. The sugar will get clumpy, then eventually start to melt until it's a dark brown liquid.
Once the sugar is all the way melted, carefully stir in 1 tablespoon of butter at a time until combined. Be very careful as the butter will bubble up as soon as you add it. If the butter looks a bit separated from the sugar (like a layer of oil on top), remove it from the heat and carefully whisk until it comes together. Watch out for oil splatter though!
Once the butter and sugar are combined, very slowly pour in the soy creamer, stirring as you pour. Once combined, let the mixture boil for 1 minute without stirring. It will bubble up in the pan, but don't let it bubble over.
Remove from the heat and stir in the salt. Let it cool down until it thickens up. It will be quite thin when hot, but thicken as it cools.
