Pat venison dry and season lightly with kosher salt.
Transfer to a cooling rack set over a baking sheet and allow to dry brine for at least 2 hours or up to 24 hours, uncovered, in the fridge.
Before cooking, bring to room temperature for 30 minutes.
Make the Sweet Corn Polenta
Blend fresh corn kernels and water until mostly smooth.
Pour into a saucepan over medium heat, stirring constantly until thickened and bubbling, about 10–12 minutes.
Reduce heat to low and stir in crème fraîche, butter, and pecorino until fully incorporated.
Season with salt and pepper. Keep warm.
Prepare the Mushrooms
Heat olive oil in a skillet over medium heat.
Add mushrooms and sauté for 5 minutes until browned.
Add balsamic vinegar and thyme, cooking until mushrooms are glazed and tender.
Sear the Venison
Heat olive oil in a cast iron skillet over medium-high heat (370-400°F).
Sear medallions for 90 seconds per side. You'll know it's ready to flip once it releases from the pan. It sticks because the crust is still forming, so don't nudge it around if it's not releasing. The protein will almost always tell you when it's ready. Transfer to a cooling rack to rest for 3 minutes.
Return to the pan and cook another 90 seconds per side or until internal temp reaches 125-130°F.
Remove and let rest for another 3 minutes. The multi-sear and rest method builds crust slowly while keeping the inside perfectly even, with no grey band and no overcooked edge.
Notes
Storage: cover and refrigerate for up to 3 days. Reheat the polenta and mushrooms gently on the stove, adding a splash of water or stock to loosen the polenta.