What temperature should butter toffee reach?
Butter toffee should reach 300-310°F (hard crack stage). Use a candy thermometer for accuracy; this ensures the toffee sets properly without burning.
Can I use salted butter instead of unsalted?
Yes, but reduce the added salt to 1/8 tsp. Unsalted butter gives you better control over the final salt balance in this recipe.
How do I prevent the toffee from crystallizing?
Avoid stirring once the mixture boils, and add the corn syrup and water to prevent sugar crystallization. Stir only while heating to melt the sugar initially.
Can I make this ahead?
Yes. Store cooled toffee in an airtight container with parchment between layers at room temperature for up to 2 weeks.
What does baking soda do in toffee?
Baking soda creates tiny air pockets, giving the toffee a lighter, crackly texture and helping it break into pieces easily.