Set your oven rack to the center position and preheat oven to 350°F (177°C). Line the bottom and sides of a 9×13-inch baking pan or 11×7-inch baking pan* with aluminum foil (or use parchment), leaving an overhang on all sides. Set aside.

Whisk the flour, cocoa powder, baking powder, and salt together in a large bowl until combined. Set aside.

In a large bowl using a handheld mixer or stand mixer with paddle attachment, beat the butter for 1 minute on medium speed until completely smooth and creamy. Add the granulated sugar and beat on medium high speed until fluffy and light in color. Beat in egg and vanilla on high speed until combined. Scrape down the sides and bottom of the bowl as needed. Beat in the food coloring until combined. With the mixer running on low speed, slowly mix the dry ingredients into the wet ingredients until combined. The red velvet dough will be quite thick and sticky.

Using a silicone spatula, spread dough in an even layer into the prepared baking pan. It’s very sticky, so take your time pushing it to each corner of the pan. Bake for 8 minutes. Remove from the oven and leave the oven on.

Sprinkle the coconut over the cookie layer, followed by the chocolate chips, then the white chocolate chips. Pour the sweetened condensed milk evenly over the top. Sprinkle with pecans. Bake until set, about 25 minutes.* Cool on a rack for at least 2 hours before cutting into squares.