In a pan on medium heat, melt butter.

Add onion, mixing into butter.

Once the onions begin the soften, add garlic, thyme and rosemary.

Saute for a couple of minutes.

Sprinkle about a tbsp of flour, mixing in.

Once mixed in, add wine.

Reduce until alcohol has burned off and the reduction is thick enough to coat a spoon. Taste reduction to ensure alcohol has burned off.

Spread reduction on each slice of bread.

Add Gruyere.

Butter the outside of each slice.

Grill in a pan on medium heat until golden brown on each side.

Serve!