Put almond flour, salt, and pepper in a large bowl and add meat, stirring to coat.
Heat oil in large skillet and add meat pieces, shaking off excess flour seasoning as you transfer them from the bowl to the skillet. Brown the meat on all sides. Use a plotted spoon to put browned pieces in the slow cooker.
Add onion and garlic to the skillet and cook, stirring, for about 3 minutes. Add paprika and cook for 1 minute, stirring constantly. Scrape this onto the meat in the slow cooker.
Add stock to the skillet, and bring to a boil, stirring to dislodge the brown bits in the skillet. Add the tomato paste to combine, and pour mixture into the slow cooker.
Cut the kidneys into clices approximately 1/4-inch thick, and put them in the slow cooker along with the bay leaves, carrots, celery, and mushrooms. Stir everything together.
Cover and cook on Low for 8 to 10 hours or on High for 5 to 7 hours. (I usually do 10 hours as the taste is stronger). Voila, I serve it with steamed veggies.