Heat olive oil and butter in a non-stick skillet over medium heat. Add the asparagus and cook, stirring occasionally for 3 minutes. Add the garlic and lemon zest and continue cooking another 2 to 5 minutes, depending on your desired level of done-ness (I like my asparagus al dente). Sprinkle with sea salt and cracked black pepper to taste.: The moment the fats shimmer and the butter has melted and begun to foam you should smell a gentle, toasty aroma, which signals the pan is ready to receive the asparagus . This controlled heat allows the outside of the spears to develop slight browning while keeping their interior tender crisp. If the pan smokes heavily, lower the heat immediately, because overheated fats will impart a bitter, acrid flavor to the vegetables.
Heat a medium-sized non-stick skillet to medium-high and add the butter and olive oil. Sprinkle the salmon fillet with sea salt and place on the hot skillet, skin-side up. Cook for 4 to 6 minutes (depending on thickness of fish), and carefully flip to the other side. Cook 3 minutes, add the garlic and lemon juice and cook another 2 to 3 minutes, until salmon is cooked through but still moist.: As the asparagus hits the pan you will hear brief sizzling, a sign of moisture searing away and surface caramelization beginning. Stir occasionally so the spears brown evenly and the tips do not overcook. For even cooking, arrange them in a single layer and avoid overcrowding, which causes steaming rather than browning and leaves them limp.
Add the garlic and lemon zest and continue cooking another 2 to 5 minutes, depending on your desired level of done-ness: When you add the minced garlic and the fragrant lemon zest the aroma will lift, filling the kitchen with citrus and roasted garlic notes, and the asparagus will develop tiny browned spots. If you prefer al dente spears aim for the lower end of the time range, while for softer spears cook a bit longer. Watch closely once the garlic is in, because it can go from sweet and aromatic to bitter within seconds if left unattended.
Sprinkle with sea salt and cracked black pepper to taste: Right after you remove the asparagus from heat, seasoning it will make the flavors pop, and the coarse texture of cracked pepper gives a pleasant contrast. Taste a spear before over salting, because the butter already adds saltiness. A common mistake is salting too early, which draws out moisture and makes the spears less crisp.
Heat a medium-sized non-stick skillet to medium-high and add the butter and olive oil: Preheating a separate skillet until it radiates even heat ensures the salmon will sear quickly, producing a golden exterior. When the butter begins to foam and the oil glistens you should hear a pronounced sizzle as the fish touches the pan, which indicates a good Maillard reaction is about to occur. If the pan is not hot enough the fish will stick and fail to develop color.
Sprinkle the salmon fillet with sea salt and place on the hot skillet, skin-side up: When the salmon hits the skillet you will hear an immediate sizzle and see the edges begin to change color, moving from translucent to opaque. Placing the fillet skin-side up first helps the initial sear set the proteins without curling, and it makes flipping easier. Resist the urge to move the fillet too soon, because early turning prevents a proper crust from forming.
Cook for 4 to 6 minutes, depending on thickness of fish: During this interval the heat will travel through the fillet, and you should see the cooked color creep up the side. The top will lose its raw sheen, and you may notice small beads of oil collecting at the surface. Thicker fillets need closer to six minutes, while thinner pieces will finish faster. Avoid overcooking, which dries the fish and dulls its natural richness.
Carefully flip to the other side: The flip is a tactile moment, and a confident, steady motion will keep the fillet intact. Once flipped, the previously exposed side will begin to form a light crust and scent the pan with warm, buttery notes. If the fish sticks, it likely needs another 30 seconds on the first side; forcing it will tear the flesh and reduce the plate's visual appeal.
Cook 3 minutes: In these three minutes the interior will finish setting while the outside deepens in color. You can often tell doneness by pressing gently near the thickest part; it should give slightly and flake where the flesh separates. If it flakes apart excessively, that is a sign of overcooking and a drier mouthfeel will result.
Add the garlic and lemon juice and cook another 2 to 3 minutes, until salmon is cooked through but still moist: When the additional garlic and bright lemon juice hit the hot pan they will deglaze residual brown bits and create a glossy, aromatic pan sauce that clings to the salmon . You will smell the citrus brighten the buttered aroma and see the sauce reduce slightly. Cook just until the center is opaque and flakes gently, because lingering in the pan will dry the fish. A common error here is adding too much acid too early, which can curdle the fats and produce a broken texture in the sauce.