Preheat oven to 350 degrees. Line a 5 x 9" loaf pan with parchment paper. Set aside.
In a mixing bowl, with a hand or stand mixer, cream together the softened butter and Swerve granular sugar substitute. Add the eggs and combine. Add the oil, Greek yogurt, lemon juice, lemon zest, and extracts. Combine until mostly smooth.
In a separate bowl, whisk together the flour, baking powder, baking soda and salt.
With the mixer running on the lowest speed, gradually add the dry ingredients to the wet ingredient mixture, stopping to scrape down the sides of the bowl.
Pour the batter evenly into the prepared pan. Bake at 350 degrees for 55-60 minutes or until toothpick inserted comes out clean and crumb free. Remove from oven and let cake cool complete.
While cake cools, mix together the frosting. In bowl, add the softened butter and Swerve confectioners sugar. Using a rubber scraper, begin combining. Add the lemon juice and lemon extract. Stir together until smooth. Frosting will be thick.
Remove cake from pan and parchment paper. Frost the top of the cooled cake. Enjoy right away or refrigerate for 30 minutes to let the frosting set up.