• Preheat the oven to 325 degrees Fahrenheit (160 degrees Celsius).
• Prepare your baking dish. Whether a 8" square (20 cm) cake pan or a rectangular loaf pan 8 1/2 x 4 1/2 (21 x 11 cm), you may want to butter the pan, but I have found using parchment paper to line the bottom and sides works much better for removing the cake easily without the mess of flour or butter.

Eggs & Sugar

• In a stand mixer or with a hand-mixer, combine the eggs and sugar on high speed for 2-3 minutes until lighter in color, ribbon-esque and beautifully smooth.
• In a small mixing bowl off to the side, place the créme fraîche and add a couple tablespoons of the egg & sugar mixture. Whisk together until the créme fraîche is lighter and smoother. Then add the créme fraiche mixture to the main bowl which holds the egg & sugar mixture. Don't use the electic or stand mixture to combine. You want to keep as much air in the eggs as possible now, so you are going to gentle whisk by hand the créme fraîche into the mixture until smooth (maybe 30 seconds). Set aside for a moment.

Dry Ingredients

• In a large bowl, mix together the flour, baking powder, salt and lemon & orange zest.

Combine the Egg & Sugar & Créme Fraîche mixture with the Dry Ingredients

• In thirds, add a third of the dry ingredient mixture to the egg-mixture. Using a spatula, gently fold all ingredients together. Then add another third of the dry-mixture, fold together gently. Then finally, add the final third and combine. Set aside for a moment.

Butter & Citrus Juice

• In a small sauce pan, melt your butter and add the juices of your lemon and orange. Over a medium heat, melt and combine - about 2-3 minutes.

Putting Everything Together

• As soon as the butter mixture has melted and combined, slowly pour it into the batter, whisking to combine.
• Pour the batter into your prepared baking pan. If you are using small individual pans, fill until just to 1/2 way up the sides.
• Bake the one large cake for about 55 minutes or until golden brown.
• Serve the same day with tea or coffee, while you can absolutely making a glaze or finishing drizzles such as Chantilly cream, merinque or even just fruit, the cake is full of flavor all on its own and will delight you and your guests.

Freezing

• Wrap well in plastic wrap and place in the freezer for up to 3-4 weeks. When you are ready to enjoy, remove from the freezer and place in the refrigerator for about 3-4 hours until you are ready to serve.