Preheat oven to 350ºF.: The warm, even heat prepares the oven to toast the rolls and melt the cheddar cheese without drying the filling. You should notice a gentle rise in ambient kitchen heat and, after a few minutes, a steady, even heat when you open the oven, which signals it is ready. Preheating is crucial so the tops brown uniformly in the time given. Common mistake to avoid is skipping preheat, which can lead to uneven melting and soggy bottoms.
Mix together the first six ingredients and set aside (or chill if making crescents later).: A creamy mixture forms as the mayonnaise binds the chopped chicken , diced celery , and seasonings together; you will smell the faint tang of Worcestershire sauce blending in. The texture should be cohesive but not watery, and the flavors should taste balanced when you sample a small spoonful. This step matters because a well combined filling ensures consistent flavor in every slider. Avoid over mixing, which can break down the chicken into mush and change the texture.
Split each dinner roll. Place roll bottoms in 9 x 13 x 2-baking pan. Top rolls with chicken salad. Top chicken salad with cheese slices. Place roll tops on top of the cheese.: When assembling, the soft, slightly sweet roll bottoms act like a pillow for the filling; you will feel the tender crumb compress slightly under gentle pressure. Spread the filling evenly so each slider gets a similar amount, then add the cheddar cheese so it melts through the filling as it bakes. The visual cue is a neat row of sandwiches filling the pan. A common mistake is overstuffing; too much filling can prevent even heating and cause collapse when you cut or pull the sliders apart.
In a small saucepan combine butter, brown sugar, mustard, Worcestershire and sesame seeds. Bring to a boil and pour over sandwiches.: As the glaze warms, the butter melts and the brown sugar dissolves, releasing a sweet molasses aroma that mingles with the tang of dijon mustard and umami of Worcestershire sauce . Bringing the mixture to a brief boil helps the sugar dissolve and emulsify with the butter , creating a glossy, pourable glaze. Pouring it over the assembled sliders distributes flavor and encourages caramelization on top. Watch the saucepan closely; overheating can cause the sugar to scorch and become bitter, so avoid prolonged high heat.
Bake for 20-30 minutes, or until the tops are brown and crispy.: During baking you will notice the scent of caramelizing sugar and the cheddar cheese melting into the filling. The tops should turn a warm golden brown and develop a slight crispness while the interior becomes hot and bubbling slightly. Tap the pan lightly and the center should feel set and warm through. This bake time allows the glaze to caramelize without burning, and the cheese to melt properly. A common error is leaving them too long which will dry the filling and harden the tops, so check at the earlier time point and adjust for your oven.