Chocolate Pretzel Beer Toffee

From The Beeroness [1]

1 cup sugar
1 cup butter
1 cup amber ale, divided
2 cups dark chocolate chips
2 cups pretzels, smashed

Into a large pot over high heat, add sugar, butter and 1/2 cup of the amber ale. Stir until the mixture begins to boil. Leave mixture untouched until it starts to darken and thicken. Continuously stir the sugar beer mixture until it reaches 290ºF. This could take between 15 and 20 minutes. Once the mixture is really dark and reaches 290ºF, pour onto a quarter baking sheet lined with parchment paper, and allow to cool. This is the first layer of the toffee.
Into a large bowl, add the chocolate. Heat remaining beer in a saucepan over medium heat until it just starts to simmer. Pour beer over the chocolate and stir until smooth and all of the chocolate is melted. Pour the melted chocolate over the toffee, and garnish with crushed pretzels. Allow the chocolate to set.
Cut into 2-inch squares.