6tablespoons (85 g) unsalted butter, room temperature
½cup (100 g) granulated sugar
¼cup (50 g) brown sugar
2large eggs, room temperature
1teaspoonvanilla extract
½cup (120 ml) sour cream or plain yogurt
½cup (120 ml) Irish cream, (such as Bailey’s)
Glaze
½cup (60 g) confectioners' sugar, sifted
2tablespoons (30 ml) Irish Cream
Instructions
Preheat the oven to 350° F. Line a 8-inch by 8-inch baking pan with parchment paper (or lightly grease with cooking spray). Set aside.
Streusel
In a medium bowl, whisk together the brown sugar, cinnamon and flour. Add the melted butter and stir until well combined. Set the topping aside.
Cake
In a medium bowl, whisk together flour, baking powder, baking soda and salt. Set aside.
In a large bowl of a stand mixer (or using a hand mixer), mix butter, granulated sugar and brown sugar together. Beat until light and fluffy, about 3 minutes. Scrape down the sides of the bowl with a rubber spatula.
With the mixer on medium-high, add eggs one at a time, beating until incorporated. Add vanilla and sour cream. Mix until combined.
Turn mixer speed to low, add half the flour mixture and mix for a few seconds. Pour in Irish cream, mix for a few more seconds. Add remaining flour mixture and mix just until combined (careful not to overmix!) Scrape down the sides of the bowl with a rubber spatula as needed.
Assembly
Pour half the batter in prepared baking pan and spread evenly. Top with half the streusel mixture. Pour remaining batter on top (spread carefully if needed). Top with remaining streusel mixture.
Bake for 40 minutes or until a toothpick inserted in the center comes out clean. Set pan on wire rack to cool for 15 minutes.
Glaze
In a small bowl, whisk together confectioners' sugar and Irish cream. Drizzle over the cake. Slice and serve.
Notes
Store sliced coffee cake in an airtight container at room temperature for up to 5 days.
Coffee cake can be made the night before. Cover cooled cake tightly with plastic wrap. Add the glaze in the morning and serve.
Coffee cake can also be frozen for up to 2 months. Defrost in the refrigerator overnight and bring to room temperature before serving.