1. In a bowl, combine the flour, baking powder, and salt; whisk them to blend.
2. In an electric mixer, beat the butter and brown sugar on medium speed for 3 minutes or until fluffy. Beat in the egg and vanilla.
3. On low speed, add the flour mixture in 2 additions, and mix until blended.
4. Remove the bowl from the mixer stand. Stir in the toffee bits.
5. Divide the dough in half. Roll 2 logs about 9 inches long and 1 1/2 inches wide. Flatten the logs into 2 1/2-inch-wide rectangles. Wrap rectangles in plastic wrap and refrigerate for 1 1/2 hours or until firm.
6. Set the oven at 350 degrees. Line 2 baking sheets with parchment paper.
7. With a long knife, cut the dough 1/4-inch thick. Transfer to baking sheets, leaving 1 inch between them. Bake for 10 to 12 minutes or until lightly browned around edges. Cool cookies completely on the sheets. Bake remaining cookies.
8. Transfer the baked cookies to a wire rack set over a rimmed baking sheet. In a heatproof bowl set over a pan of barely simmering water, heat the chocolate chips, stirring occasionally, until they melt. Stir in the oil and mix until smooth.
9. Holding one side of the cookies, dip a part of each one into the chocolate or drizzle the chocolate over the cookies with a spoon. Sprinkle pecans on top. Let the chocolate set about 1 hour. Adapted from "Cook's Country"