Preheat oven to 400 degrees and butter a muffin pan.

Cut circles out of bread slices (about 3 inches in diameter) using a cookie cutter or similar.

Whisk eggs, brown sugar, cinnamon, and nutmeg together in a bowl.

Dredge bread circles in the egg mixture, removing any excess.

Press the dredged bread circles into the buttered muffin pan.

Bake in the preheated oven for 12 to 15 minutes, or until golden brown.

While the French toast cups are baking, prepare the sausage.

In a skillet, cook the breakfast sausage until browned.

In another hot skillet, melt butter.

Stir in brown sugar, cinnamon, nutmeg, and vanilla extract into the melted butter.

Add diced apples to the brown sugar mixture and cook until the apples begin to soften and the sugar mixture caramelizes.

Combine the cooked sausage and any drippings with the apple mixture and stir.

Once the French toast cups are done, let them cool for a few minutes before removing them from the pan using a knife to separate them.

Fill each French toast cup with the apple and sausage mixture.

Drizzle with maple syrup (optional).

Serve immediately.