Make the Cookies:

1. Preheat the oven to 350F, and line two large cookie sheets with parchment paper.
2. Using a stand mixer fitted with a paddle attachment, cream together the butter and brown sugar on medium speed until well combined. Beat in the egg and vanilla extract.
3. In a second mixing bowl, combine the flour, espresso powder, baking powder, salt and toffee bits. Add to the wet ingredients, and beat on low speed until combined.
4. Roll the dough into 1-inch round balls, and arrange on prepared baking sheets. Using your thumb, press a deep indent into the middle of each ball.
5. Bake in preheated oven for 10-12 minutes, or until golden-brown. Let cool on the baking sheet for 2-3 minutes, then transfer to a wire rack to finish cooling completely.

Fill the Cookies:

1. While the cookies are cooling, place the caramels and cream in a small microwave-safe bowl and microwave on High for 30 seconds, or until melted and smooth. (If necessary, continue to microwave in 10-second increments until the caramels are melted, stirring between bursts.)
2. Spoon a small amount of caramel into the centre of each cookie. Let cool for 15-20 minutes before serving to allow the caramel to set.