Preheat the oven to 350°F (175°C). Prepare a 9-inch cake pan by lining the bottom with a circle of parchment paper and greasing the sides.

In a medium-sized bowl, combine 0.75 cup all-purpose flour, 0.75 cup packed brown sugar, 1 tsp ground cinnamon, 1 cup toffee bits, and 0.25 cup melted butter. Mix with a fork until all ingredients are well incorporated and crumbly. Set aside.

In a large bowl, beat 0.5 cup brown sugar and 6 tbsp room temperature butter until light in color and fluffy, about 3-4 minutes.

Add 0.25 cup sour cream and 0.25 cup milk to the mixture and mix until well incorporated.

Add 1 large egg and 1 tsp almond extract and mix until smooth.

In a separate bowl, whisk together 1 cup all-purpose flour and 1.25 tsp baking powder.

Gradually add the dry ingredients to the wet batter and mix until just smooth. Be careful not to overmix.

Spread half of the cake batter evenly into the bottom of the prepared 9-inch cake pan.

Top the batter with approximately half of the streusel mixture, scattering it evenly.

Carefully spread the remaining cake batter over the streusel layer.

Sprinkle the remaining streusel over the top of the cake batter.

Bake for 28-30 minutes, or until a wooden toothpick inserted into the center comes out with a few moist crumbs attached.

Remove the cake from the oven and allow it to cool in the pan for about 15 minutes. Then, carefully remove it to a wire rack to cool completely.

While the cake cools, prepare the glaze: In a small bowl, combine 0.75 cup powdered sugar, 2 tbsp milk, and 0.25 tsp almond extract. Whisk until smooth. Add additional milk or powdered sugar, a teaspoon at a time, until the glaze reaches a drizzling consistency.

Once the cake is cooled, drizzle the almond glaze over the top. If desired, sprinkle with slivered almonds and extra toffee bits for garnish.

Store the coffee cake in an airtight container at room temperature. The cake should be enjoyed within 3-4 days.