Grease and line a 9x9-inch baking dish with parchment paper.
In a large mixing bowl, cream together the sugar and melted butter until light and fluffy, beating for about 2 minutes.
Mix in the eggs and vanilla until well incorporated.
In a separate bowl, whisk together the cocoa powder, flour, salt, and baking powder until combined.
Add half of the dry mixture to the butter mixture and beat well, then fold in the remaining dry ingredients just until combined.
Spread the batter into your prepared baking dish.
Press the cherry cordials gently into the batter, spacing them evenly throughout.
Bake for 25-30 minutes, until the center feels firm and the edges start to pull away from the pan.
Allow to cool completely before frosting.
For the frosting, beat together the butter, powdered sugar, cherry syrup, and milk until smooth and creamy, adjusting the consistency as needed with additional milk or sugar.
Once the brownies have cooled, spread the frosting evenly over the top using an offset spatula.
Scatter the chopped cherry cordials over the frosting.
In a microwave-safe bowl, heat the chocolate chips for 35 seconds, then stir.
Continue heating in short bursts until fully melted.
Mix in the shortening to thin the chocolate.
Drizzle the melted chocolate over the brownies in a decorative pattern.
Allow everything to set completely before slicing into squares and serving.
Notes
Cool brownies completely before frosting. Press whole cherry cordials gently into batter before baking. Add shortening to chocolate for easier drizzling. Let frosting set before cutting for cleanest slices.