This is the best streusel cake I've ever eaten. The flavor combination is just delicious. It's easy to make and makes a delightful addition to any breakfast, brunch, church or office potluck gathering.
Preheat oven to 350°F. Grease & flour a 9 or 10 inch tube or bundt pan. Set aside.
In a medium bowl, use a spatula or spoon to mix together the light brown sugar and orange zest. Add the flour and almonds and toss to coat. Stir in the melted butter and toss until you have an even crumble topping. Set aside.
In a separate mixing bowl, combine the dry ingredients - flour, baking powder and baking soda. Set aside.
In a large bowl using an electric mixer on medium speed, beat together butter and sugar until fluffy. Add eggs, one at a time, beating over low speed just until combined. Add the orange zest, vanilla extract, almond emulsion and mix to combine.
With the mixer on low speed, alternate adding the flour mixture and orange juice to the egg mixture, starting and ending with flour. Mix only to combine. Don't over mix batter.
Spoon half the batter into the prepared tube or bundt pan. Using a spatula, spread it evenly. Sprinkle half of the streusel crumb mixture. Top with remaining batter and streusel topping.
Tap the pan a few times on the counter or table to remove any air bubbles. Bake for 30-35 minutes until toothpick inserted in the center comes out clean. Transfer pan to cooling rack to cool.
In a Pyrex measuring cup, stir together the powdered sugar, orange juice, orange zest and splash of Grand Marnier until smooth.
Once the cake has cooled slightly, invert the cake out onto a serving plate, streusel side up.
Drizzle with the glaze. Serve warm or at room temperature.