1. Melt 1 1/2 T butter with 1 1/2 T olive oil in a 12"saute pan. Add onions and stir in 1/2 tsp salt. Cover and cook, stirring occasionally, until onions are limp, about 8 min. Uncover and sprinkle with sugar. Increase heat to medium-high and stir often until onions begin to brown, 5-7 min. Add balsamic vinegar and 1 1/2 tsp. thyme leaves; stir often until liquid has evaporated, 1-2 min longer.

2. Rinse steaks and pat dry. Sprinkle both sides lightly with salt, then coat with peppercorns. Melt remaining 1/2 tabl butter and olive oil in a 12 inch saute pan over med. heat. Add steaks and cook until well browned on one side. Turn over and cook until beginning to brown on other side, abt 2 min. Transfer pan to a 375 degree oven and bake until medium-rare (still pink in the center; cut to test), 7-8 min, or until as done as you like (steaks will continue cooking for a few minutes after you take them out of the oven.

3. Transfer steaks to warm plates. Spoon onions over the top and sprinkle with remaining 1 1/2 teaspoons thyme.