Grease bottom and sides of 15x10x1-inch pan with shortening or cooking spray (do not use dark pan).
To Make Crust
In large bowl, beat ¾ cup butter and ⅓ cup brown sugar with electric mixer on medium speed until light and fluffy. Add egg; beat until well blended. On low speed, beat in flour until dough begins to form. Press dough in pan.
Bake 12 to 17 minutes or until edges are light golden brown.
To Make Filling
In a medium saucepan, melt butter, brown sugar and the corn syrup, over medium-heat, stirring until combined.
Bring to boiling over medium heat, stirring frequently. Boil 2 minutes without stirring.
Quickly stir pecans into corn syrup mixture; spread over partially baked crust. Bake 20 to 23 minutes or until filling is golden brown and bubbly.
Immediately sprinkle chocolate chips evenly over hot bars.
Let pan sit for 5 minutes to soften chips.
With rubber spatula, gently swirl melted chips over bars.
Cool completely, about 1 hour. For bars, cut into 24 squares (6 rows by 4 rows), then cut each square in half to make triangles.
Store in refrigerator.
Notes
My notes: When you are boiling the butter sugar mixture for the filling, do not leave the stove. It can burn easily if you’re not careful. Once in the bar pan, the edges of my bars got a little extra brown—I’m not sure if that’s the sugary mixture on top or what. So I guess just pay attention to that when baking. Also, I couldn’t find the swirl chips so used a combination of chocolate and butterscotch chips.