Soft, buttery sheet cake is swirled with a luscious cinnamon roll filling and then drenched in sweet glaze.--this is one addicting cinnamon roll sheet cake!
Preheat oven to 350F. Lightly grease a 9x13 baking pan. Set aside. In a large bowl, beat butter and sugar together until completely creamy. Beat egg in one at a time until smooth, then add milk and vanilla.
In a separate bowl, combine flour, baking powder, and salt. Fold into liquid mixture until batter is just combined. Scrape batter into prepared pan and set aside.
Cinnamon Swirl
In a small bowl, whisk melted butter, sugar, and cinnamon until smooth and creamy. Drop by the tablespoon over batter and gently use a knife to swirl the batter and cinnamon together.
Bake sheet cake at 350F 20-25 minutes or until golden brown and a toothpick tests done. Cool on a wire cooling rack.
Glaze
In a small bowl, whisk all glaze ingredients until smooth. Drizzle over cooled cake and let stand 10 minutes before slicing and serving. Enjoy!