Prepare the cake batter: Preheat oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan.

Cream butter and sugar: In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla extract.

Combine dry ingredients: In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, alternating with the milk, and mix until just combined.

Divide the batter: Divide the batter in half. In one bowl, add a few drops of red food coloring and mix until evenly colored. In the other bowl, add a few drops of yellow food coloring and mix until evenly colored.

Bake the cake: Pour the red batter into the prepared pan, spreading it evenly. Pour the yellow batter on top of the red batter, spreading it evenly. Bake for 45 minutes, or until a toothpick inserted into the center comes out clean.

Assemble the cake: Let the cake cool completely in the pan. While the cake is cooling, prepare the apricot glaze by heating the apricot jam in a small saucepan over low heat until melted and smooth.

Cut and glaze: Once the cake is cool, use a sharp knife to cut the cake in half lengthwise. Spread the apricot glaze evenly over one half of the cake, then place the other half on top, aligning the edges.

Dust with powdered sugar: Dust the top of the cake with powdered sugar and cut into squares or rectangles.

Enjoy!