Butter a loaf pan, 8 1/2 or 9 inch, and place it on a baking sheet.
In a large bowl, whisk the gluten-free flour, baking powder, salt and baking soda and whisk to combine.
In a small bowl, add the eggs, honey and sugar and whisk until smooth. Add the grated zest and juice and whisk to combine. Add the egg mixture to the dry ingredients in three additions, using a flexible spatula to gently mix the batter. Still working with the spatula, slowly incorporate the olive oil. You’ll have a thick, smooth batter with a light sheen from the oil.
Pour the batter into the pan and gently jiggle the pan a couple of times to even out the batter.
Bake the cake until a tester inserted deep into the center of the cake comes out clean. Check the cake after 30 minutes and tent lightly with foil if it’s getting too dark too quickly,. Transfer the cake to a rack and let sit for 5 minutes before unmolding and turning it right side up onto the rack.
To glaze the cake (optional): Warm a few spoonful of marmalade along with a splash of water in a small bowl and heat in the microwave until warm. Glaze the cake with a brush as soon as it is unmolded.
Allow the cake to come to room temperature before serving.