In a deep bowl, whisk together the sugar, lemon zest and thyme to combine all the flavors. Add the eggs and whisk until you get a homogeneous mixture. Add sour cream and olive oil. Finally add the flour, salt and lemon juice. Mix everything well. Place the prepared mixture in a rectangular pan 20 x 25 cm coated with oil and lined with baking paper. Bake at 170 °C for about 40 minutes. Mix the powdered sugar with 4 tablespoons of lemon in a bowl aside. Pour this mixture over the cooled cake. Garnish with slices of fresh lemon and thyme leaves.