Preheat oven to 80C. Place serving dish for four steaks inside to warm.
Split breast by cutting each breast in half horizontally to form 4 thin steaks in total.
Sprinkle each side with salt and pepper, then sprinkle with flour and use your fingers to spread it all over the surface.
Melt 15g butter in a large non-stick frying pan over medium-high heat. Add chicken and cook each side for 2 1/2 minutes until golden brown and just cooked through. Remove from pan to serving dish and keep warm in the oven.
In the same frying pan, add remaining butter and increase heat to medium-high. Add garlic and a pinch of salt and pepper, and continue cooking for another minute until the garlic is just turning golden. Add white wine, cook for 30 seconds, scraping the bottom of the pan until wine is mostly evaporated and the alcohol smell is gone.
Add chicken stock, cook vigorously for 1 minute so it mostly evaporates. Then add cream, lower heat to medium and simmer for 2 minutes until it reduces and thickens slightly.