In a large bowl, cream butter, olive oil, and sugar. Add eggs one at a time, blending after each. Begin folding in flour, baking powder, salt, zest, nutmeg and fennel pollen. Add yogurt or lebne and continue gently folding a few more times. Add grated zucchini and Le Gruyère cheese; continue folding until evenly distributed and smooth.
Pour into prepared loaf pan. Bake 35-40 minutes or just until a toothpick comes out clean when inserted in the top of the bread. Serve warm.