Preheat oven to 350°F. Grease and flour a 9-inch round cake pan.
For Cake: Combine corn syrup, milk, dissolved coffee and vanilla in a small bowl. Set aside. Beat butter in a large mixing bowl. Sift flour, sugar, baking powder, baking soda and salt over butter. Add brown sugar, egg, egg yolk and half the coffee mixture. Mix on low speed of electric mixer to combine. Increase speed to medium and beat 1 minute. Scrape sides of bowl, then add remaining coffee mixture; beat 1 minute longer. Spread batter in prepared pan.
Bake 27 to 32 minutes until cake is golden brown and toothpick inserted in center comes out clean. Cool in pan 15 minutes. Remove to wire rack. Cool completely before frosting.
For Coffee Buttercream Frosting:Combine all ingredients in a large mixing bowl. Beat until light and fluffy. Add additional milk, 1 teaspoon at a time, if needed, to reach desired spreading consistency.
Frost cake with Coffee Buttercream Frosting. Top with toasted almonds. Serve with a cold glass of milk…or coffee!
Note: Instant coffee powders vary considerably in flavor and strength. You may adjust the amounts of instant coffee powder to taste.