In large nonstick skillet over medium-high heat, heat 1/2 teaspoon oil until hot. Combine salt and 1/4 teaspoon pepper. Press evenly onto all surfaces of roast. Place roast in skillet; brown evenly. Remove roast from skillet.

Heat oven to 425 F.

In food processor, pulse mushrooms and shallot about 10 times until finely chopped. Do not overprocess.

Place same skillet used for roast over medium-high heat and heat remaining oil until hot. Add mushrooms and shallot; cook 4-6 minutes until tender and all liquid is evaporated, stirring often. Add wine; cook 2-3 minutes until all liquid is evaporated. Stir in mustard, thyme and remaining pepper. Cook 2-3 minutes. Remove from skillet to medium bowl; cool.

Line rimmed baking sheet with aluminum foil and place in oven. On lightly floured cutting board, unfold pastry dough. Roll pastry out to 12-by-9-inch rectangle; lay dough with shortest edge toward you. Spread mushroom mixture onto pastry dough, leaving 1/2-inch border around edges. Place roast in center of mushrooms. Fold pastry dough neatly around roast, stretching dough if necessary. Cut off excess pastry dough; press to seal overlapping edges.

Remove baking sheet from oven and dust lightly with flour. Place pastry-wrapped roast, seam-side down, on baking sheet. Cut four (2-inch) vents in top of pastry.

Bake 35-50 minutes, or until golden brown and instant-read thermometer inserted into center of roast registers 135 F for medium-rare or 150 F for medium. Transfer roast to carving board. Let stand 10 minutes. Temperature will rise about 10 F to reach 145 F for medium-rare or 160F for medium.

Carve into slices and serve.