Preheat the oven to 350°F (175°C). Grease a round cake pan and set aside.
Mix the dry ingredients: in a large bowl, sift together the flour and combine with granulated sugar.
2 cups all-purpose flour, 1 cup granulated sugar
Add softened butter to the dry mixture and use an electric mixer or a pastry cutter to combine until the mixture resembles coarse crumbs.
1/2 cup unsalted butter
In a separate bowl, beat the eggs, milk, and vanilla extract until well combined. Dissolve the coffee powder in a small amount of hot water and add to the wet mixture.
2 large eggs, 1 cup milk, 1 tablespoon instant coffee powder, 1 teaspoon vanilla extract
Gradually add the wet mixture to the dry ingredients, mixing gently until just combined to form a smooth batter.
Pour half of the batter into the prepared cake pan, spreading evenly with a spatula.
In a mixing bowl, whip the heavy cream and powdered sugar until stiff peaks form. Spread this coffee-flavored cream evenly over the batter layer in the pan.
1 cup heavy cream, 1/2 cup powdered sugar
Pour the remaining batter over the cream layer, smoothing the top slightly.
Prepare the streusel topping by mixing flour, brown sugar, cinnamon, and cold cubed butter with a pastry cutter until crumbly.
1 cup plain all-purpose flour, 1/2 cup brown sugar, 1/2 cup unsalted butter, 1/2 teaspoon ground cinnamon
Sprinkle the streusel evenly over the top of the batter in the pan.
Bake the cake in the preheated oven for 35 minutes, or until a toothpick inserted into the center comes out clean and the top is golden brown.
Remove the cake from the oven and let it cool in the pan for 15 minutes before transferring to a wire rack to cool completely.
