Warning: this recipe involves very hot, molten sugar. Keep children away until the toffee has cooled and handle the pot and toffee carefully.

Line a standard baking sheet or a 9x13-inch pan with parchment paper and spray the parchment lightly with cooking spray. Do not skip the parchment.

In a large, high-sided pot combine 2 cups (4 sticks) unsalted butter, 2 cups granulated sugar, 1 teaspoon salt, and 1 teaspoon vanilla extract. Clip a candy thermometer to the side of the pot. Use a pot larger than you think you'll need—the mixture will bubble up.

Heat the mixture over medium heat. Stir only until the butter melts and the sugar is combined; once it reaches a boil stop stirring. Cook until the candy thermometer reads 285°F, which typically takes about 20–30 minutes.

When the mixture reaches 285°F, immediately pour the hot toffee into the prepared parchment-lined pan. If needed, gently tilt the pan so the toffee spreads into an even layer. Let the toffee rest undisturbed for 5–10 minutes so it firms slightly but is still pliable.

After 5–10 minutes, score grooves into the still-warm toffee with a knife or pizza cutter to make later breaking easier. You do not need to cut fully through—just make grooves. Aim for about 12–15 large squares or up to 24 bite-sized pieces, as you prefer.

Allow the toffee to cool completely at room temperature until fully set and firm (at least 30–60 minutes, longer if needed).

Once firm, remove the toffee from the pan and break it into pieces along the scored lines. If any butter has leaked out and remains on the surface, gently pat it off with paper towels.

In a medium bowl combine 1/2 cup granulated sugar and 1 tablespoon cinnamon; stir to blend thoroughly. You can leave this in the bowl or spread it on parchment for easier sprinkling.

Melt one 10-ounce bag of Ghirardelli White Melting Wafers in a medium, microwave-safe bowl or in a heatproof bowl over simmering water. If using a microwave, heat in 20–30 second increments, stirring between each, until smooth. If using a double boiler, stir until smooth. Melt more of the wafers as needed—the recipe includes three 10-ounce bags total to be used as required.

Working quickly, dip each toffee piece into the melted white chocolate so the piece is coated as desired. Place dipped pieces on parchment.

Immediately spoon the cinnamon-sugar over the top and sides of each coated piece, or press the piece into the cinnamon-sugar, to coat evenly. Continue dipping and coating, melting additional white wafers when needed.

Let the coated toffee set at room temperature until the white chocolate is firm, about 60–90 minutes. (Avoid refrigerating if possible, as the cinnamon-sugar can become slightly wet in the fridge.)

Store finished churro toffee airtight at room temperature for up to 2 weeks or in the freezer for up to 4 months. Thaw fully before serving.