• Preheat the oven to 350˚F. Butter the bottom and sides of an 8-inch or 9-inch round pan. Then, line the pan with a round piece of parchment paper. Set aside. You can use a springform pan if you'd like. Just make sure to butter the sides well. 
• Melt butter in a small saucepan or a medium-size microwave-safe bowl for about 50 seconds. 
• Add the melted butter, sugar, eggs, orange zest, and vanilla extract in a large mixing bowl. Whisk together until blended. Add the ricotta and stir until incorporated about 30 seconds.
• Add the flour, baking powder, and salt to the ricotta mixture and fold until the flour is incorporated. 
• Pour the batter into the prepared pan. Smooth the top with a spatula and hit it against the counter a few times to release bubbles.
•  Place in a preheated oven and bake for 25-35 minutes or until the cake has a small dome in the center, is lightly golden brown, and springs back when lightly touched on the top.
• Remove from oven and allow to cool for 10 minutes. 
• Invert onto a cooling rack and let the cake cool completely before adding the icing. If I'm in a bind, I'll place the cake in the freezer for 10 minutes to cool quickly. You can't ice the cake when warm, as the icing will melt off. 

Orange Buttercream Icing

• Melt the butter in a microwave-safe bowl or a small saucepan.
• Add all of the icing ingredients and whisk together until smooth and creamy. It should be easy to spread. If it is too thick, add more cream and whisk.
• Scoop and spread over the cooled cake. Decorate with orange slices or edible flowers.